Medium severity · published May 11, 2026
CVE-2026-41257
jq: Signed-int overflow in `stack_reallocate` (jq VM stack)
5.5
CVSS
0.1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
JQ
jq · jqlang
<= 1.8.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41257
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-41257
Exploit
https://github.com/jqlang/jq/security/advisories/GHSA-4jm8-m363-4539
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