Medium [CVE-2026-47770] Denial of Service via deeply nested array comparison

jq is a command-line JSON processor. Prior to 1.8.2, comparing two sufficiently deeply nested arrays with the == operator exhausts the C stack on jq's ordinary command-line surface, resulting in denial of service via stack exhaustion (uncontrolled recursion).

The crash occurs in jq's recursive structural comparison code, with the recursion repeating through jvp_array_equal() and jv_equal() in src/jv.c when comparing deeply nested arrays; a nearby sort comparator path through jv_cmp() in src/jv_aux.c overflows the stack at a larger nesting depth from the same missing recursion guard.

Anyone running jq comparisons on attacker-controlled deeply nested JSON values, or embedding jq in a context where untrusted data can reach the == comparison path, is affected. This vulnerability is fixed in 1.8.2.

This vulnerability allows a local user or an attacker providing malicious input to cause a denial of service (DoS) by comparing two sufficiently deeply nested arrays using the '==' operator. This action exhausts the C stack due to uncontrolled recursion, leading to a crash of the jq process.

Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H). Weakness: CWE-770.

Affected products named by the advisory: Red Hat Hardened Images; Red Hat Ansible Automation Platform 2; Red Hat Ceph Storage 4; Red Hat Enterprise Linux 10; and 4 more.