Inefficient regular expression complexity in markdown-it - CVE-2026-2327
Published: November 6, 2026
Vulnerability identifier: #VU159520
CSH Severity: Medium
CVSS v4: 6.9 [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]
CVE-ID: CVE-2026-2327
CWE-ID: CWE-1333
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to the use of the regex /*+$/ in the linkify function. A remote attacker can supply a long sequence of * characters followed by a non-matching character, which triggers excessive backtracking and may lead to a denial-of-service condition.
Affected software
markdown-it
QRadar Pre-Validation App
QRadar Pre-Validation App
How to mitigate CVE-2026-2327
Cybersecurity Help is currently unaware of any official solution to address this vulnerability..
markdown-it - update to 14.1.1
QRadar Pre-Validation App - update to 3.0.0
QRadar Pre-Validation App - update to 3.0.0
External References
- https://gist.github.com/ltduc147/c9abecae1b291ede4f692f2ab988c917
- https://github.com/markdown-it/markdown-it/blob/14.1.0/lib/rules_inline/linkify.mjs%23L33
- https://github.com/markdown-it/markdown-it/commit/4b4bbcae5e0990a5b172378e507b33a59012ed26
- https://security.snyk.io/vuln/SNYK-JS-MARKDOWNIT-10666750