Service interruption via runtime regex backtracking
Published Feb 11, 2026 · Updated Aug 28, 2026
Regular expression denial of service in Ajv before 6.14.0 and 7.0.0 through 8.17.1 allows remote attackers to block API services. The pattern keyword passes a $data-referenced runtime value directly to JavaScript RegExp(), then tests attacker-controlled input and triggers exponential backtracking. Exploitation requires $data to be enabled and an application path that lets the attacker control both the dynamic pattern and tested value; successful requests block the Node.js event loop.
Summary
What happened
Regular expression denial of service in Ajv before 6.14.0 and 7.0.0 through 8.17.1 allows remote attackers to block API services. The pattern keyword passes a $data-referenced runtime value directly to JavaScript RegExp(), then tests attacker-controlled input and triggers exponential backtracking. Exploitation requires $data to be enabled and an application path that lets the attacker control both the dynamic pattern and tested value; successful requests block the Node.js event loop.
The record
- CVE
- CVE-2025-69873
- Published
- Feb 11, 2026
- Updated
- Aug 28, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Quay
- Classifications
- CWE-1333, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Ajv $data ReDoS proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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