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Public proof of concept

CVE-2025-6493

A public proof of concept exists; no exploitation attested.

  • Published2025-06-22
  • WeaknessCWE-1333 · CWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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."

Timeline

dates in UTC
  1. 2025-06-2222:15CVE publishedNVD

Versions per branch

Products declared by the CNA1 product

As VulDB, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • CodeMirror
    Affected
    • = 5.65.0no fix stated
    • = 5.65.1no fix stated
    • = 5.65.2no fix stated
    • = 5.65.3no fix stated
    • = 5.65.4no fix stated
    • = 5.65.5no fix stated
    • = 5.65.6no fix stated
    • = 5.65.7no fix stated

    14 more version lines in the CVE record.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2025-09-29

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • codemirror-jsUbuntu:26.10all versions · no fixed version listed
  • codemirror-jsUbuntu:26.04:LTSall versions · no fixed version listed
  • codemirror-jsUbuntu:25.10all versions · no fixed version listed
  • codemirror-jsUbuntu:24.04:LTSall versions · no fixed version listed
  • codemirror-jsUbuntu:22.04:LTSall versions · no fixed version listed
  • codemirror-jsUbuntu:20.04:LTSall versions · no fixed version listed
  • codemirror-jsUbuntu:18.04:LTSall versions · no fixed version listed
  • codemirror-jsUbuntu:16.04:LTSall versions · no fixed version listed

3 more package ranges on OSV.dev

Vendor advisories

  • CVE-2025-6493 Red Hat Product Security

    codemirror: CodeMirror Markdown Regex Complexity Vulnerability

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2025-06-23
  • CNACVSS 4.05.5known since 2026-10-23
  • CNACVSS 3.15.3known since 2026-10-23
  • CNACVSS 2.05known since 2026-10-23
  • CNAweakness (CWE)CWE-1333, CWE-400known since 2026-10-23
  • FIRST EPSSEPSS score0.5 %2026-11-09
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 4.0 vector
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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2025-06-22
Last Modified
2026-06-17
NVD status
Deferred
GitHub Advisory
GHSA-pff4-9qxc-79mq

Frequently asked questions

What is CVE-2025-6493?

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."

Is CVE-2025-6493 actively exploited?

A proof-of-concept exploit exists for CVE-2025-6493, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2025-6493?

CVE-2025-6493 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

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Sources for this record