CVE-2026-116795
RE2JS: Quadratic-time denial of service in re2js lookbehind matching
HIGH 7.5EPSS 0.5%
RE2JS is the JavaScript port of RE2, a regular expression engine that provides linear time matching. From 2.2.0 until 2.8.7, enabling LOOKBEHINDS and using repeated matching through matcher().find(), matchAll(), split(), or matcher().replaceAll() can cause quadratic total work. Machine.match restarts lookbehind scanning from offset zero for each requested start position, while Matcher-based APIs request capture slots that prevent the early exit used for captureless matching. Dense matches therefore repeatedly rescan the input, allowing attacker-influenced text to monopolize a single-threaded worker and deny service. This issue is fixed in version 2.8.7.
- Affected
- le0pard · re2js
- CVSS v3.1 GITHUB
- 7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.46% chance of exploitation in the next 30 days, 40th percentile
- Published
- 2026-10-28
Proof-of-concept exploits (1)
CVE references
- le0pard/re2js/commit/dfdd947785dfa113bdc97416375c246a39458395REFERENCE
- le0pard/re2js/pull/59REFERENCE
- le0pard/re2js/releases/tag/2.8.7REFERENCE
- le0pard/re2js/security/advisories/GHSA-gg6h-894w-4m9cREFERENCE