What’s Vulnerable › Vulnerabilities

CVE-2022-21681: Exponential catastrophic backtracking (ReDoS) in marked

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-01-14 · updated 2026-06-17
• Weakness: CWE-400

Description

Marked is a markdown parser and compiler. Prior to version 4.0.10, the regular expression `inline.reflinkSearch` may cause catastrophic backtracking against some strings and lead to a denial of service (DoS). Anyone who runs untrusted markdown through a vulnerable version of marked and does not use a worker with a time limit may be affected. This issue is patched in version 4.0.10. As a workaround, avoid running untrusted markdown through marked or run marked on a worker thread and set a reasonable time limit to prevent draining resources.

Affected products

• Fedoraproject Fedora: 36
• markedjs marked: before 4.0.10 — fixed in 4.0.10
• Npm Marked: before 4.0.10 — fixed in 4.0.10

How to fix

Upgrade to a fixed version: markedjs marked 4.0.10; Npm Marked 4.0.10. Check the vendor advisory for mitigations.

References

• https://github.com/markedjs/marked/commit/8f806573a3f6c6b7a39b8cdb66ab5ebb8d55a5f5
• https://github.com/markedjs/marked/security/advisories/GHSA-5v2h-r2cx-5xgj
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AIXDMC3CSHYW3YWVSQOXAWLUYQHAO5UX/
• https://github.com/markedjs/marked/commit/8f806573a3f6c6b7a39b8cdb66ab5ebb8d55a5f5
• https://github.com/markedjs/marked/security/advisories/GHSA-5v2h-r2cx-5xgj
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AIXDMC3CSHYW3YWVSQOXAWLUYQHAO5UX/

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