CVE-2026-39979: jqlang jq · Out-of-bounds Read
Affects jqlang jqSource CVE Database V5
Not known to be exploited · CVSS 6.9 Medium.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 13 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| jqlangjq | Affected
| Fixed in– |
AI-suggested
A patch fixing this vulnerability is available in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f. Users and vendors consuming libjq should update to versions including this commit. Red Hat advisories reference fixes in their packages; users of affected Red Hat products should apply the relevant security updates as provided in the Red Hat errata. Patch status is confirmed by vendor advisories. No additional mitigations are specified beyond applying the official fix.
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.
References
- github.com/jqlang/jq/security/advisories/GHSA-2hhh-px8h-355p (opens in a new tab)
- github.com/jqlang/jq/commit/2f09060afab23fe9390cce7cb860b10416e1bf5f (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-39979 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2458077 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39979.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26528 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26542 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:28887 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23233 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:25044 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:34098 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:25181 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23245 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:16252 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18048 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18047 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18046 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18045 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18044 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18040 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:16692 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19151 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18043 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:18042 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:16693 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19365 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:25096 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30078 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30089 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30088 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:30087 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:8579 (opens in a new tab)