# CVE-2026-39956: jq: Missing runtime type checks for _strindices lead to crash and limited memory disclosure CVE-2026-39956 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-2026-39956 - Priority: Routine - CVSS: 6.1 (Moderate) - EPSS: 0.0017 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 13, 2026 - Weakness: Out-of-bounds Read - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-39956 ## Description jq is a command-line JSON processor. Prior to version 1.8.2, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03, which is part of version 1.8.2. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | jq Debian 12.15 (bookworm) | 1.6-2.1+deb12u2 | [DEBIAN-CVE-2026-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2026-39956.md) | Apr 13, 2026 | | Linux | jq Debian 13.5 (trixie) | 1.7.1-6+deb13u2 | [DEBIAN-CVE-2026-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2026-39956.md) | Apr 13, 2026 | | Linux | jq Debian 14 | 1.8.1-5 | [DEBIAN-CVE-2026-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2026-39956.md) | Apr 13, 2026 | | Linux | jq Fedora 43 | 1.8.1-3.fc43 | [FEDORA-2026-4E57162966](https://patchblox.com/security/data/fix/linux/fedora-2026-4e57162966.md) | Apr 16, 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 15.7 | 1.6-150000.3.20.1 | [SUSE-SU-2026:2983-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2983-1.md) | Jul 14, 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 Fedora 43 | 1.8.1-3.fc43 | [FEDORA-2026-4E57162966](https://patchblox.com/security/data/fix/linux/fedora-2026-4e57162966.md) | Apr 16, 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 Fedora 43 | 1.8.1-3.fc43 | [FEDORA-2026-4E57162966](https://patchblox.com/security/data/fix/linux/fedora-2026-4e57162966.md) | Apr 16, 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 Fedora 43 | 1.8.1-3.fc43 | [FEDORA-2026-4E57162966](https://patchblox.com/security/data/fix/linux/fedora-2026-4e57162966.md) | Apr 16, 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 2026-11-09T13:31:49Z UTC. 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