CVE-2025-69873: Ajv Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-2g4f-4pwh-qvx6
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CWE-400 CWE-1333
Published
Advisory Summary

CVE-2025-69873 is a MODERATE denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Ajv libraries in the npm ecosystem. The issue involves ajv has redos when using `$data` option. Remediation is available by upgrading affected packages to version 8.18.0, 6.14.0.

CVE-2025-69873 at a Glance

CVE Identifier CVE-2025-69873
GHSA Identifier GHSA-2g4f-4pwh-qvx6
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Ajv
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2025-69873

To remediate this vulnerability, upgrade all affected Ajv dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ajv fixed: 8.18.0 
npm install ajv@8.18.0
ajv fixed: 6.14.0 
npm install ajv@6.14.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls ajv

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-69873, inspect your project dependencies using npm:

npm ls ajv

Analyze the terminal output to locate any version of Ajv in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 8.18.0), your application is affected.

Note: The npm ls ajv command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Ajv, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

ajv (Another JSON Schema Validator) through version 8.17.1 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.

CVE-2025-69873 Affected Ajv Versions

2 component(s)
Fixed Versions:
8.18.06.14.0
Product / Package Ecosystem Affected Versions Fixed Version
ajv
npm/ajv
npm
≥ 7.0.0-alpha.0
< 8.18.0
8.18.0
ajv
npm/ajv
npm
< 6.14.0
6.14.0

References

NVD — CVE-2025-69873 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-69873
Ajv Source Repository REPOSITORY
https://github.com/ajv-validator/ajv/pull/2586
Ajv Source Repository REPOSITORY
https://github.com/ajv-validator/ajv/pull/2588
Ajv Source Repository REPOSITORY
https://github.com/ajv-validator/ajv/pull/2590
Ajv Source Repository REPOSITORY
https://github.com/github/advisory-database/pull/6991
Security Fix Commit FIX COMMIT
https://github.com/ajv-validator/ajv/commit/720a23fa453ffae8340e92c9b0fe886c54cfe0d5
Ajv Source Repository REPOSITORY
https://github.com/EthanKim88/ethan-cve-disclosures/blob/main/CVE-2025-69873-ajv-ReDoS.md
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-2g4f-4pwh-qvx6
Ajv Source Repository REPOSITORY
https://github.com/ajv-validator/ajv
Ajv Release RELEASE
https://github.com/ajv-validator/ajv/releases/tag/v6.14.0
Ajv Release RELEASE
https://github.com/ajv-validator/ajv/releases/tag/v8.18.0

Frequently Asked Questions

What is CVE-2025-69873?
CVE-2025-69873 is a security vulnerability in Ajv involving ajv has ReDoS when using `$data` option under CWE-400: Uncontrolled Resource Consumption.
Which Ajv versions are affected?
Affected versions include releases prior to 8.18.0, 6.14.0 across affected packages: ajv.
What version fixes CVE-2025-69873?
Upgrading to 8.18.0, 6.14.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ajv affected?
Yes, ajv is affected in releases prior to 8.18.0, 6.14.0. Upgrade your dependency to 8.18.0, 6.14.0 or later.
What CWE is associated with CVE-2025-69873?
CVE-2025-69873 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2025-69873?
Run the dependency tree command: 'npm ls ajv'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2g4f-4pwh-qvx6",
  "modified" : "2026-03-02T21:58:39Z",
  "published" : "2026-02-11T21:30:39Z",
  "aliases" : [ "CVE-2025-69873" ],
  "summary" : "ajv has ReDoS when using `$data` option",
  "details" : "ajv (Another JSON Schema Validator) through version 8.17.1 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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "ajv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0-alpha.0"
      }, {
        "fixed" : "8.18.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "ajv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.14.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-69873"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/pull/2586"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/pull/2588"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/pull/2590"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/github/advisory-database/pull/6991"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/commit/720a23fa453ffae8340e92c9b0fe886c54cfe0d5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/EthanKim88/ethan-cve-disclosures/blob/main/CVE-2025-69873-ajv-ReDoS.md"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-2g4f-4pwh-qvx6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ajv-validator/ajv"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/releases/tag/v6.14.0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ajv-validator/ajv/releases/tag/v8.18.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333", "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-17T16:38:57Z",
    "nvd_published_at" : "2026-02-11T19:15:50Z"
  }
}