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CVE-2026-39979

jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
jqlang / jqaffected < 2f09060afab23fe9390cce7cb860b10416e1bf5f

CWE

CWE-125

References

ADP enrichment

CISA-ADP

No English description supplied.

redhat-SADP

A flaw was found in jq, a command line JSON processor, specifically in the libjq API. Parsing a malformed JSON input from a non-NUL-terminated buffer using the `jv_parse_sized` function can cause an out-of-bounds read, resulting in an application crash and a possible memory disclosure within the error message generated by the parser.