CVE-2026-40612 jq: Stack overflow via unbounded recursion in jv_contains
Attackers can cause a stack overflow and crash the application by providing deeply nested JSON structures to the jq library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-40612?
CVE-2026-40612 is a medium-severity denial of service vulnerability in jqlang jq, published on 11 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
jq is a command-line JSON processor. In 1.8.1 and earlier, jv_contains recurses into nested arrays/objects with no depth limit. With a sufficiently nested input structure (built programmatically with reduce, since the JSON parser caps at depth 10000), the C stack is exhausted.
Weakness: CWE-674
Which versions are affected by CVE-2026-40612?
It affects 1 product.
Products include Jqlang Jq.
How do I fix CVE-2026-40612?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-40612 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40612 exists.
Other vulnerabilities in jqlang jq
- CVE-2026-32316 jq: Integer overflow in jvp_string_append() allows Heap-based Buffer Overflow
- CVE-2024-53427 Memory corruption in jq
- CVE-2025-48060 AddressSanitizer: stack-buffer-overflow in jq_fuzz_execute (jv_string_vfmt)
- CVE-2023-49355 Memory corruption in n/a
- CVE-2026-49839 jq --rawfile invalid-state reuse after String too long causes heap-buffer-overflow
Sources
Also known as ALPINE-CVE-2026-40612, AZL-86381, BELL-CVE-2026-40612, DEBIAN-CVE-2026-40612, ECHO-1e5b-f6f3-755b, GHSA-r7m6-x9c7-h69j and 1 more.