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CVE-2025-69873VulnerabilityPublished Updated

CVE-2025-69873: ajv · ReDoS

Affects ajvSource CVE Database V5

0

Not known to be exploited · CVSS 2.9 Low : upgrade to 8.17.2 or 6.14.0 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
2.9Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 8.17.2, 6.14.0
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade ajv to 8.17.2 or 6.14.0.

Affected software

ProductAffectedFixed in
ajv.jsajvAffected
  • <6.14.0
  • >=7.0.0 <8.17.2
Fixed in
  • 8.17.2
  • 6.14.0

AI-suggested

A fix is available in ajv version 8.18.0. Users should upgrade to this or a later version to remediate the vulnerability. If upgrading is not immediately possible, the vendor advisory recommends disabling the $data feature if it is not required. If $data must be used, strict validation of input fields referenced by the pattern keyword should be implemented to ensure only expected and safe characters are accepted.

Description

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.

References

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