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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4599-1 jq security update
Debian DLA Debian DLA DLA-4662-1 jq security update
Ubuntu USN Ubuntu USN USN-8202-2 jq vulnerabilities
Ubuntu USN Ubuntu USN USN-8202-1 jq vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

References
Link Providers
https://access.redhat.com/errata/RHSA-2026:16252 cve-icon
https://access.redhat.com/errata/RHSA-2026:16692 cve-icon
https://access.redhat.com/errata/RHSA-2026:16693 cve-icon
https://access.redhat.com/errata/RHSA-2026:18040 cve-icon
https://access.redhat.com/errata/RHSA-2026:18042 cve-icon
https://access.redhat.com/errata/RHSA-2026:18043 cve-icon
https://access.redhat.com/errata/RHSA-2026:18044 cve-icon
https://access.redhat.com/errata/RHSA-2026:18045 cve-icon
https://access.redhat.com/errata/RHSA-2026:18046 cve-icon
https://access.redhat.com/errata/RHSA-2026:18047 cve-icon
https://access.redhat.com/errata/RHSA-2026:18048 cve-icon
https://access.redhat.com/errata/RHSA-2026:19151 cve-icon
https://access.redhat.com/errata/RHSA-2026:19365 cve-icon
https://access.redhat.com/errata/RHSA-2026:23233 cve-icon
https://access.redhat.com/errata/RHSA-2026:23245 cve-icon
https://access.redhat.com/errata/RHSA-2026:25044 cve-icon
https://access.redhat.com/errata/RHSA-2026:25096 cve-icon
https://access.redhat.com/errata/RHSA-2026:25181 cve-icon
https://access.redhat.com/errata/RHSA-2026:26528 cve-icon
https://access.redhat.com/errata/RHSA-2026:26542 cve-icon
https://access.redhat.com/errata/RHSA-2026:28887 cve-icon
https://access.redhat.com/errata/RHSA-2026:30078 cve-icon
https://access.redhat.com/errata/RHSA-2026:30087 cve-icon
https://access.redhat.com/errata/RHSA-2026:30088 cve-icon
https://access.redhat.com/errata/RHSA-2026:30089 cve-icon
https://access.redhat.com/errata/RHSA-2026:34098 cve-icon
https://access.redhat.com/errata/RHSA-2026:8579 cve-icon
https://access.redhat.com/security/cve/CVE-2026-39979 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2458077 cve-icon
https://github.com/jqlang/jq/commit/2f09060afab23fe9390cce7cb860b10416e1bf5f cve-icon cve-icon cve-icon
https://github.com/jqlang/jq/security/advisories/GHSA-2hhh-px8h-355p cve-icon cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-39979 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39979.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-39979 cve-icon
History

Thu, 23 Apr 2026 17:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'}

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'}


Wed, 15 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'}

threat_severity

Important


Tue, 14 Apr 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Jqlang
Jqlang jq
Vendors & Products Jqlang
Jqlang jq

Tue, 14 Apr 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 13 Apr 2026 22:45:00 +0000

Type Values Removed Values Added
Description 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.
Title jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers
Weaknesses CWE-125
References
Metrics cvssV4_0

{'score': 6.9, 'vector': '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-15T01:01:40.651Z

Reserved: 2026-04-08T00:01:47.628Z

Link: CVE-2026-39979

cve-icon Vulnrichment

Updated: 2026-07-10T12:05:54.906Z

cve-icon NVD

Status : Modified

Published: 2026-04-13T23:16:27.823

Modified: 2026-07-15T02:20:54.453

Link: CVE-2026-39979

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-13T22:18:56Z

Links: CVE-2026-39979 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-14T16:32:52Z

Weaknesses