Vulnerability record · CVE-2026-39979 · published 13 April 2026
CVE-2026-39979: Jqlang jq out-of-bounds read vulnerability
Jqlang · Jq
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.
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.
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
Affected products
14 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
Jq Jqlang
Ai Inference Server Redhat
Ansible Automation Platform Redhat
Ceph Storage Redhat
Codeready Linux Builder Redhat
Codeready Linux Builder Eus Redhat
Enterprise Linux Redhat
Enterprise Linux Aus Redhat
Enterprise Linux Eus Redhat
Enterprise Linux Tus Redhat
Enterprise Linux Update Services For Sap Solutions Redhat
Hardened Images Redhat
Openshift Ai Redhat
Openshift Container Platform Redhat
References
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-39979), CISA KEV, FIRST EPSS (scores of 2026-11-13). This page is refreshed as NVD updates the record.
