What’s Vulnerable › Vulnerabilities

CVE-2025-6493: CodeMirror Markdown Mode markdown.js redos

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-06-22 · updated 2026-06-17
• Weakness: CWE-400

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."

Affected products

• CodeMirror: 5.65.0, 5.65.1, 5.65.2, 5.65.3, 5.65.4, 5.65.5 (+15)

References

• https://github.com/codemirror/codemirror5/issues/7128
• https://vuldb.com/?ctiid.313610
• https://vuldb.com/?id.313610
• https://vuldb.com/?submit.598875

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