CVE-2026-40164 (GCVE-0-2026-40164)

Vulnerability from cvelistv5 – Published: 2026-04-13 23:40 – Updated: 2026-04-13 23:40
VLAI?
Title
jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed
Summary
jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table operations, which allowed an attacker to precompute key collisions offline. By supplying a crafted JSON object (~100 KB) where all keys hashed to the same bucket, hash table lookups degraded from O(1) to O(n), turning any jq expression into an O(n²) operation and causing significant CPU exhaustion. This affected common jq use cases such as CI/CD pipelines, web services, and data processing scripts, and was far more practical to exploit than existing heap overflow issues since it required only a small payload. This issue has been patched in commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784.
CWE
  • CWE-328 - Use of Weak Hash
  • CWE-407 - Inefficient Algorithmic Complexity
Assigner
Impacted products
Vendor Product Version
jqlang jq Affected: < 0c7d133c3c7e37c00b6d46b658a02244fdd3c784
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Show details on NVD website

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          "vendor": "jqlang",
          "versions": [
            {
              "status": "affected",
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            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
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          "descriptions": [
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              "description": "CWE-328: Use of Weak Hash",
              "lang": "en",
              "type": "CWE"
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        {
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      "providerMetadata": {
        "dateUpdated": "2026-04-13T23:40:12.693Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      "source": {
        "advisory": "GHSA-wwj8-gxm6-jc29",
        "discovery": "UNKNOWN"
      },
      "title": "jq: Algorithmic complexity DoS via hardcoded MurmurHash3 seed"
    }
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    "cveId": "CVE-2026-40164",
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    "dateReserved": "2026-04-09T19:31:56.014Z",
    "dateUpdated": "2026-04-13T23:40:12.693Z",
    "state": "PUBLISHED"
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  }
}


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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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