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CVE-2025-69873
February 11, 2026
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.
Affected Packages
https://github.com/ajv-validator/ajv.git (GITHUB):
Affected version(s) >=v5.1.0 <v6.14.0
Fix Suggestion:
Update to version v6.14.0
https://github.com/ajv-validator/ajv.git (GITHUB):
Affected version(s) >=v7.0.0-alpha.0 <v8.18.0
Fix Suggestion:
Update to version v8.18.0
ajv (NPM):
Affected version(s) >=0.0.4 <6.14.0
Fix Suggestion:
Update to version 6.14.0
ajv (NPM):
Affected version(s) >=7.0.0-alpha.0 <8.18.0
Fix Suggestion:
Update to version 8.18.0
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CVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
2.9
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
Uncontrolled Resource Consumption
Inefficient Regular Expression Complexity
EPSS
Base Score:
0.07