CVE-2025-6493

CodeMirror Markdown Mode markdown.js redos

State: Published
Severity: 6.9 Medium
Published: Jun 22, 2025
Updated: Sep 29, 2025
Reserved: Jun 22, 2025

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."

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P	VulDB
3.1	5.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C	VulDB
3.0	5.3 Medium	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	VulDB
2.0	5.0 Medium	AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C	VulDB

Weaknesses

CWE-1333 Inefficient Regular Expression Complexity
CWE-400 Resource Consumption

Affected Products

Product	Versions
CodeMirrorn/a	5.65.0Affected 5.65.1Affected 5.65.2Affected 5.65.3Affected 5.65.4Affected 5.65.5Affected 5.65.6Affected 5.65.7Affected 5.65.8Affected 5.65.9Affected 5.65.10Affected 5.65.11Affected 5.65.12Affected 5.65.13Affected 5.65.14Affected 5.65.15Affected 5.65.16Affected 5.65.17Affected 5.65.18Affected 5.65.19Affected 5.65.20Affected 6.0Not affected

References

VDB-313610 | CodeMirror Markdown Mode markdown.js redosvdb-entrytechnical-description
VDB-313610 | CTI Indicators (IOB, IOC, TTP, IOA)signaturepermissions-required
Submit #598875 | codemirror codemirror5 <=5.17.0 Inefficient Regular Expression Complexitythird-party-advisory
https://github.com/codemirror/codemirror5/issues/7128exploitissue-tracking

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