High · CVSS 7.5CVE-2026-116795

RE2JS: Quadratic-time denial of service in re2js lookbehind matchingCVE-2026-116795

Answer in brief

CVE-2026-116795 records a High severity (CVSS 7.5) vulnerability in RE2JS: Quadratic-time denial of service in re2js lookbehind matching. The current sources do not mark it as known exploited. The current feed maps le0pard/re2js (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 28, 2026Updated Oct 28, 2026Source checked Oct 28, 2026First seen by HOL Oct 28, 2026Material review Oct 28, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps le0pard/re2js (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
le0pard/re2jsgeneric	>=2.2.0 <2.8.7	2.8.7

Recommended response

Check inventory. Check lockfiles and deployed manifests for le0pard/re2js.
Review the reported fix. Update le0pard/re2js to 2.8.7 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 28, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.