# CVE-2026-33948: jq: Embedded-NUL Truncation in CLI JSON Input Path Causes Prefix-Only Validation of Malformed Input CVE-2026-33948 is fixed in 5 products on 1 platform, first by jq 1.5+dfsg-2ubuntu0.1~esm2, released April 13, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-33948 - Priority: Routine - CVSS: 5.3 (Low) - EPSS: 0.0026 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 13, 2026 - Weakness: Improper Null Termination - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33948 ## Description jq is a command-line JSON processor. Commits before 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contain a vulnerability where CLI input parsing allows validation bypass via embedded NUL bytes. When reading JSON from files or stdin, jq uses strlen() to determine buffer length instead of the actual byte count from fgets(), causing it to truncate input at the first NUL byte and parse only the preceding prefix. This enables an attacker to craft input with a benign JSON prefix before a NUL byte followed by malicious trailing data, where jq validates only the prefix as valid JSON while silently discarding the suffix. Workflows relying on jq to validate untrusted JSON before forwarding it to downstream consumers are susceptible to parser differential attacks, as those consumers may process the full input including the malicious trailing bytes. This issue has been patched by commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | jq Debian 12.15 (bookworm) | 1.6-2.1+deb12u2 | [DEBIAN-CVE-2026-33948](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33948.md) | Apr 14, 2026 | | Linux | jq Debian 13.5 (trixie) | 1.7.1-6+deb13u2 | [DEBIAN-CVE-2026-33948](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33948.md) | Apr 14, 2026 | | Linux | jq Debian 14 | 1.8.1-5 | [DEBIAN-CVE-2026-33948](https://patchblox.com/security/data/fix/linux/debian-cve-2026-33948.md) | Apr 14, 2026 | | Linux | jq Ubuntu 18.04.6 LTS (bionic) | 1.5+dfsg-2ubuntu0.1~esm2 | [jq 1.5+dfsg-2ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-jq-1.5-dfsg-2ubuntu0.1-esm2.md) | Apr 13, 2026 | | Linux | jq Ubuntu 20.04 LTS (focal) | 1.6-1ubuntu0.20.04.1+esm2 | [jq 1.6-1ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-jq-1.6-1ubuntu0.20.04.1-esm2.md) | Apr 13, 2026 | | Linux | jq Ubuntu 22.04.1 LTS (jammy) | 1.6-2.1ubuntu3.2 | [jq 1.6-2.1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-jq-1.6-2.1ubuntu3.2.md) | Apr 13, 2026 | | Linux | jq Ubuntu 24.04.5 LTS (noble) | 1.7.1-3ubuntu0.24.04.2 | [jq 1.7.1-3ubuntu0.24.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-jq-1.7.1-3ubuntu0.24.04.2.md) | Apr 13, 2026 | | Linux | jq Ubuntu 25.10 (questing) | 1.8.1-3ubuntu1.1 | [jq 1.8.1-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-jq-1.8.1-3ubuntu1.1.md) | Apr 13, 2026 | | Linux | jq Ubuntu 26.04.1 LTS (resolute) | 1.8.1-4ubuntu2 | [jq 1.8.1-4ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-jq-1.8.1-4ubuntu2.md) | Apr 13, 2026 | | Linux | jq amzn 2023 | 1.8.1-59.amzn2023 | [ALAS2023-2026-1815](https://patchblox.com/security/data/fix/linux/alas2023-2026-1815.md) | Jun 8, 2026 | | Linux | jq opensuse-leap 16.0 | 1.7.1-160000.3.1 | [OPENSUSE-SU-2026:21248-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21248-1.md) | Jul 7, 2026 | | Linux | jq sles 15.6 | 1.7.1-150000.3.25.1 | [SUSE-SU-2026:4275-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4275-1.md) | Sep 21, 2026 | | Linux | jq sles 15.7 | 1.7.1-150000.3.25.1 | [SUSE-SU-2026:4275-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4275-1.md) | Sep 21, 2026 | | Linux | jq sles 16.0 | 1.7.1-160000.3.1 | [SUSE-SU-2026:22566-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22566-1.md) | Jul 7, 2026 | | Linux | jq-debuginfo amzn 2023 | 1.8.1-59.amzn2023 | [ALAS2023-2026-1815](https://patchblox.com/security/data/fix/linux/alas2023-2026-1815.md) | Jun 8, 2026 | | Linux | jq-debugsource amzn 2023 | 1.8.1-59.amzn2023 | [ALAS2023-2026-1815](https://patchblox.com/security/data/fix/linux/alas2023-2026-1815.md) | Jun 8, 2026 | | Linux | jq-devel amzn 2023 | 1.8.1-59.amzn2023 | [ALAS2023-2026-1815](https://patchblox.com/security/data/fix/linux/alas2023-2026-1815.md) | Jun 8, 2026 | | Linux | libjq1 Ubuntu 18.04.6 LTS (bionic) | 1.5+dfsg-2ubuntu0.1~esm2 | [libjq1 1.5+dfsg-2ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libjq1-1.5-dfsg-2ubuntu0.1-esm2.md) | Apr 13, 2026 | | Linux | libjq1 Ubuntu 20.04 LTS (focal) | 1.6-1ubuntu0.20.04.1+esm2 | [libjq1 1.6-1ubuntu0.20.04.1+esm2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libjq1-1.6-1ubuntu0.20.04.1-esm2.md) | Apr 13, 2026 | | Linux | libjq1 Ubuntu 22.04.1 LTS (jammy) | 1.6-2.1ubuntu3.2 | [libjq1 1.6-2.1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libjq1-1.6-2.1ubuntu3.2.md) | Apr 13, 2026 | | Linux | libjq1 Ubuntu 24.04.5 LTS (noble) | 1.7.1-3ubuntu0.24.04.2 | [libjq1 1.7.1-3ubuntu0.24.04.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libjq1-1.7.1-3ubuntu0.24.04.2.md) | Apr 13, 2026 | | Linux | libjq1 Ubuntu 25.10 (questing) | 1.8.1-3ubuntu1.1 | [libjq1 1.8.1-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libjq1-1.8.1-3ubuntu1.1.md) | Apr 13, 2026 | | Linux | libjq1 Ubuntu 26.04.1 LTS (resolute) | 1.8.1-4ubuntu2 | [libjq1 1.8.1-4ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libjq1-1.8.1-4ubuntu2.md) | Apr 13, 2026 | --- Data as of 2026-11-09T01:18:40Z UTC. 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