CVE-2025-69873

What it is

ajv (Another JSON Schema Validator) before 8.18.0 is vulnerable to Regular Expression Denial of Service (ReDoS) when the $data option is enabled. The pattern keyword accepts runtime data via JSON Pointer syntax ($data reference), which is passed directly to the JavaScript RegExp() constructor without validation. An attacker can inject a malicious regex pattern (e.g., "^(a|a)*$") combined with crafted input to cause catastrophic backtracking. A 31-character payload causes approximately 44 seconds of CPU blocking, with each additional character doubling execution time. This enables complete denial of service with a single HTTP request against any API using ajv with $data: true for dynamic schema validation. This issue is also fixed in version 6.14.0.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-02-11 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-10 13:17 UTC Last updatedMost recent change to the record

Details

Published

2026-02-11 19:15 UTC

Last modified

2026-09-10 13:17 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-1333

Record status

Deferred

Attack profile CVSS 3.1 · 2.9

Attack vector

Local

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low