CVE-2026-39979 (GCVE-0-2026-39979)

Vulnerability from cvelistv5 – Published: 2026-04-13 22:18 – Updated: 2026-04-13 22:18
VLAI?
Title
jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers
Summary
jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f.
CWE
Assigner
Impacted products
Vendor Product Version
jqlang jq Affected: < 2f09060afab23fe9390cce7cb860b10416e1bf5f
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  "containers": {
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          "product": "jq",
          "vendor": "jqlang",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2f09060afab23fe9390cce7cb860b10416e1bf5f"
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        }
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            "attackRequirements": "NONE",
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            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "NONE"
          }
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      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-125",
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      "providerMetadata": {
        "dateUpdated": "2026-04-13T22:18:56.252Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
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        }
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      "source": {
        "advisory": "GHSA-2hhh-px8h-355p",
        "discovery": "UNKNOWN"
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      "title": "jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers"
    }
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-39979",
    "datePublished": "2026-04-13T22:18:56.252Z",
    "dateReserved": "2026-04-08T00:01:47.628Z",
    "dateUpdated": "2026-04-13T22:18:56.252Z",
    "state": "PUBLISHED"
  },
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  }
}


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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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