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.
Published: 2026-10-28
Score: 7.5 High
EPSS: n/a
KEV: No
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Remediation

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History

Wed, 28 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
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.
Title RE2JS: Quadratic-time denial of service in re2js lookbehind matching
Weaknesses CWE-1333
CWE-407
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-28T17:14:15.988Z

Reserved: 2026-10-26T21:53:35.168Z

Link: CVE-2026-116795

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-28T18:17:14.303

Modified: 2026-10-28T18:17:14.303

Link: CVE-2026-116795

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T18:45:07Z

Weaknesses
  • CWE-1333

    Inefficient Regular Expression Complexity

  • CWE-407

    Inefficient Algorithmic Complexity