Vulnerability · Published May 11, 2026 · Assigned by GitHub_M

CVE-2026-41256jq: Embedded NUL truncates top-level jq programs loaded with -f

Medium 5.5

In plain English

A medium-severity security flaw in jq from jqlang. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.5Medium
Exploit odds (30 days)0.2%top 95.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

jq is a command-line JSON processor. In 1.8.1 and earlier, Top-level jq programs loaded from a file with -f are truncated at the first embedded NUL byte on current upstream HEAD. A crafted filter file such as . followed by \x00 and arbitrary suffix compiles and executes as only the prefix before the NUL. This leaves jq with a post-CVE-2026-33948 prefix/full-buffer mismatch on the compilation path even though the JSON parser path has already been fixed.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.22jq1.8.2-r0ALPINE-CVE-2026-41256
Alpine:v3.23jq1.8.2-r0ALPINE-CVE-2026-41256
Alpine:v3.24jq1.8.2-r0ALPINE-CVE-2026-41256
Debian:12jq1.6-2.1+deb12u2DEBIAN-CVE-2026-41256
Debian:13jq1.7.1-6+deb13u3DEBIAN-CVE-2026-41256
Debian:14jq1.8.1-6DEBIAN-CVE-2026-41256
Ubuntu:22.04:LTSjqno fix listedUBUNTU-CVE-2026-41256
Ubuntu:24.04:LTSjqno fix listedUBUNTU-CVE-2026-41256
Ubuntu:25.10jqno fix listedUBUNTU-CVE-2026-41256
Ubuntu:26.04:LTSjqno fix listedUBUNTU-CVE-2026-41256
Ubuntu:26.10jqno fix listedUBUNTU-CVE-2026-41256

Affected products (as reported)

VendorProductVersions
jqlang jq <= 1.8.1

Weakness: CWE-158 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

References