Resource exhaustion in Codemirror
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."
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.005 (43.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.001
Affected products
- Codemirror — versions 5.65.0, 5.65.1, 5.65.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- vuldb.com/ (technical-description, vdb-entry)
- vuldb.com/ (signature, permissions-required)
- vuldb.com/ (third-party-advisory)
- github.com/codemirror/codemirror5/issues/7128 (issue-tracking, exploit)
Frequently asked questions
- What is CVE-2025-6493?
- CVE-2025-6493 is a medium-severity vulnerability in Codemirror, classified under Uncontrolled Resource Consumption. CVSS score: 5.3/10. Published 2025-06-22.
- How severe is CVE-2025-6493?
- Medium severity. CVSS v3 base score is 5.3 out of 10.
- Is CVE-2025-6493 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.