Quick answers
- Is CVE-2026-41257 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-41257 being exploited in the wild.
- How severe is CVE-2026-41257?
- Medium severity, with a CVSS score of 5.5, published 11 May 2026.
- Which products and versions are affected?
- Jqlang Jq <= 1.8.1.
- Is there a fix for CVE-2026-41257?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-41257 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-41257?
- Check whether you run Jqlang Jq at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An integer overflow vulnerability exists in the jq bytecode VM's data stack management within `src/exec_stack.h`. The stack uses a signed integer (`stack_ptr`) to track allocation sizes. When the stack grows beyond approximately 1 GiB via deeply nested generator forks, the doubling arithmetic in `stack_reallocate` overflows. This results in a truncated or wrapped value being passed to `realloc` and subsequently used in a `memmove` operation with attacker-influenced offsets. While often resulting in a Denial of Service (abort due to failed allocation), specific recursion depths could lead to an out-of-bounds heap write. No patch was available at the time of the advisory.
Affected products
- jqlang jq <= 1.8.1
Timeline
- 2026-04-24: advisory: GitHub Security Advisory published
- 2026-05-11: disclosed: CVE-2026-41257 published to NVD