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Sanitization bypass using HTML Entities in marked

Moderate severity GitHub Reviewed Published Feb 18, 2019 to the GitHub Advisory Database • Updated Sep 7, 2023

Package

npm marked (npm)

Affected versions

< 0.3.6

Patched versions

0.3.6

Description

Affected versions of marked are susceptible to a cross-site scripting vulnerability in link components when sanitize:true is configured.

Proof of Concept

This flaw exists because link URIs containing HTML entities get processed in an abnormal manner. Any HTML Entities get parsed on a best-effort basis and included in the resulting link, while if that parsing fails that character is omitted.

For example:

A link URI such as

javascript&#x58document;alert&#40;1&#41;

Renders a valid link that when clicked will execute alert(1).

Recommendation

Update to version 0.3.6 or later.

References

Published to the GitHub Advisory Database Feb 18, 2019
Reviewed Jun 16, 2020
Last updated Sep 7, 2023

Severity

Moderate

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS score

0.087%
(38th percentile)

Weaknesses

CVE ID

CVE-2016-10531

GHSA ID

GHSA-vfvf-mqq8-rwqc

Source code

No known source code
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