jq is a command-line JSON processor. Prior to commit 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 causes an out-of-bounds read past the end of the buffer when malformed JSON is passed in a non-NUL-terminated buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input and can result in memory disclosure or process termination depending on memory layout. The issue has been patched in the referenced commit.

The vulnerability allows an out-of-bounds read when processing malformed JSON in non-NUL-terminated buffers, potentially leading to memory disclosure or process termination. This impacts any application using libjq's jv_parse_sized() API with untrusted input. The CVSS 4.0 base score is 6.9 (medium severity), indicating a moderate impact with network attack vector, low complexity, no privileges or user interaction required, and limited confidentiality and availability impact.

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.