CVE-2026-39956

jq is a command-line JSON processor. Prior to version 1.8.2, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03, which is part of version 1.8.2.

CVSS 3.1

6.1CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

EPSS

0.2% chance of exploitation in the next 30 days; higher than 6% of CVEs (scores of 2026-10-26)

CWEs

CWE-125, CWE-476, CWE-843

Published

2026-04-13

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• jqlang:jq

References

• https://github.com/jqlang/jq/commit/fdf8ef0f0810e3d365cdd5160de43db46f57ed03
• https://github.com/jqlang/jq/security/advisories/GHSA-6gc3-3g9p-xx28
• https://github.com/jqlang/jq/security/advisories/GHSA-6gc3-3g9p-xx28

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