## RE2JS: Quadratic-time denial of service in re2js lookbehind matching

- 種別: advisory
- 重大度: high
- 関連技術: nodejs
- CVE: CVE-2026-116795
- 公開日時: 2026-10-28T21:10:01.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-gg6h-894w-4m9c)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-gg6h-894w-4m9c

影響: npm:re2js >= 2.2.0, < 2.8.7 → 2.8.7
Using the opt-in LOOKBEHINDS flag together with any repeated-matching API (matcher().find() in a loop, matchAll(), split(), matcher().replaceAll()) causes quadratic-time (Θ(n²)) matching, contradicting the library's own "linear time matching" guarantee. A single call with a 16,000-character input takes 36.7–38.7 seconds of CPU. Description Root cause In build/index.cjs, Machine.match: js let currentPos = this.prog.numLb > 0 ? 0 : pos; // ~line 1907 ... if (this.ncap === 0 && this.matched) break…