Buffer overflow in Jqlang Jq
CVE-2026-41257
jq is a command-line JSON processor. In 1.8.1 and earlier, the jq bytecode VM's data stack tracks its allocation size in a signed int. When the stack grows beyond ≈1 GiB (via deeply nested generator forks), the doubling arithmetic overflows. The wrapped value is passed to realloc and then used for a memmove with attacker-influenced offsets.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: -0.000
Affected products
- Jqlang Jq — versions <= 1.8.1
Weakness classification (CWE)
References
- github.com/jqlang/jq/security/advisories/GHSA-4jm8-m363-4539 (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-41257?
- CVE-2026-41257 is a medium-severity vulnerability in Jqlang Jq, classified under Integer Overflow or Wraparound. CVSS score: 5.5/10. Published 2026-05-11.
- How severe is CVE-2026-41257?
- Medium severity. CVSS v3 base score is 5.5 out of 10.