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OpenSSH server (sshd) 9.1 introduced a double-free...

Critical severity Unreviewed Published Feb 3, 2023 to the GitHub Advisory Database • Updated Mar 7, 2024

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be triggered by an unauthenticated attacker in the default configuration; however, the vulnerability discoverer reports that "exploiting this vulnerability will not be easy."

References

Published by the National Vulnerability Database Feb 3, 2023
Published to the GitHub Advisory Database Feb 3, 2023
Last updated Mar 7, 2024

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.761%
(82nd percentile)

Weaknesses

CVE ID

CVE-2023-25136

GHSA ID

GHSA-w62j-g234-3f6f

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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