CVE-2025-6493 - CVE House
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Status published Medium CVE-2025-6493

CodeMirror Markdown Mode markdown.js redos

Vulnerability Description

A weakness has been identified in CodeMirror up to 5.65.20. Affected is an unknown function of the file mode/markdown/markdown.js of the component Markdown Mode. This manipulation causes inefficient regular expression complexity. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be exploited. Upgrading to version 6.0 is able to address this issue. You should upgrade the affected component. Not all code samples mentioned in the GitHub issue can be found. The repository mentions, that "CodeMirror 6 exists, and is [...] much more actively maintained."

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • DayShift (VulDB User)

Affected Vendor

Affected Software

CodeMirror
Vulnerable Versions:
5.65.0, 5.65.1, 5.65.2, 5.65.3, 5.65.4, 5.65.5, 5.65.6, 5.65.7, 5.65.8, 5.65.9, 5.65.10, 5.65.11, 5.65.12, 5.65.13, 5.65.14, 5.65.15, 5.65.16, 5.65.17, 5.65.18, 5.65.19, 5.65.20, 6.0

Timeline

Official Publish: June 22nd, 2025
Last Modified: September 29th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C

Weaknesses (CWE)