CVE-2026-39979

NameCVE-2026-39979
Descriptionjq 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
jq (PTS)bullseye1.6-2.1vulnerable
bullseye (security)1.6-2.1+deb11u1vulnerable
bookworm1.6-2.1+deb12u1vulnerable
trixie1.7.1-6+deb13u1vulnerable
forky, sid1.8.1-4vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
jqsource(unstable)(unfixed)

Notes

https://github.com/jqlang/jq/security/advisories/GHSA-2hhh-px8h-355p
Fixed by: https://github.com/jqlang/jq/commit/2f09060afab23fe9390cce7cb860b10416e1bf5f

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