CVE-2026-116795 RE2JS: Quadratic-time denial of service in re2js lookbehind matching
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-116795?
CVE-2026-116795 is a high-severity vulnerability in le0pard re2js, published on 28 Oct 2026.
Official description
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.
Which versions are affected by CVE-2026-116795?
2 open source packages ship an affected version, including re2js.
| Package | Affected | Fixed in |
|---|---|---|
re2js npm | From 2.2.0 | 2.8.7 |
re2js npm | From 2.2.0 | 2.8.7 |
How do I fix CVE-2026-116795?
Upgrade re2js to 2.8.7 or later.
Is CVE-2026-116795 being exploited?
There is no known exploitation of CVE-2026-116795 in the wild and no public exploit code.
Sources
Also known as ECHO-3abd-6fdf-e676, GHSA-gg6h-894w-4m9c.