{"id":"UBUNTU-CVE-2026-39956","details":"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.","modified":"2026-09-16T14:01:44.630791123Z","published":"2026-04-13T23:16:00Z","related":["USN-8202-1","USN-8202-2"],"upstream":["CVE-2026-39956"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-39956"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-39956"},{"type":"REPORT","url":"https://github.com/jqlang/jq/security/advisories/GHSA-6gc3-3g9p-xx28"},{"type":"REPORT","url":"https://github.com/jqlang/jq/commit/fdf8ef0f0810e3d365cdd5160de43db46f57ed03"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8202-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8202-2"}],"affected":[{"package":{"name":"jq","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5+dfsg-1ubuntu0.1+esm4"}]}],"versions":["1.4-2.1","1.5+dfsg-1","1.5+dfsg-1ubuntu0.1","1.5+dfsg-1ubuntu0.1+esm2","1.5+dfsg-1ubuntu0.1+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.5+dfsg-1ubuntu0.1+esm4","binary_name":"jq"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5+dfsg-2ubuntu0.1~esm2"}]}],"versions":["1.5+dfsg-2","1.5+dfsg-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"jq","binary_version":"1.5+dfsg-2ubuntu0.1~esm2"},{"binary_version":"1.5+dfsg-2ubuntu0.1~esm2","binary_name":"libjq1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6-1ubuntu0.20.04.1+esm2"}]}],"versions":["1.5+dfsg-2build1","1.6-1","1.6-1ubuntu0.20.04.1","1.6-1ubuntu0.20.04.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"jq","binary_version":"1.6-1ubuntu0.20.04.1+esm2"},{"binary_name":"libjq1","binary_version":"1.6-1ubuntu0.20.04.1+esm2"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6-2.1ubuntu3.2"}]}],"versions":["1.6-2.1ubuntu2","1.6-2.1ubuntu3","1.6-2.1ubuntu3.1"],"ecosystem_specific":{"binaries":[{"binary_name":"jq","binary_version":"1.6-2.1ubuntu3.2"},{"binary_name":"libjq1","binary_version":"1.6-2.1ubuntu3.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.7.1-3ubuntu0.24.04.2"}]}],"versions":["1.6-3","1.7-1","1.7.1-2","1.7.1-3","1.7.1-3build1","1.7.1-3ubuntu0.24.04.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.7.1-3ubuntu0.24.04.2","binary_name":"jq"},{"binary_name":"libjq1","binary_version":"1.7.1-3ubuntu0.24.04.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/jq?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.1-3ubuntu1.1"}]}],"versions":["1.7.1-3ubuntu1","1.7.1-6ubuntu1","1.8.1-3ubuntu1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.8.1-3ubuntu1.1","binary_name":"jq"},{"binary_version":"1.8.1-3ubuntu1.1","binary_name":"libjq1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}},{"package":{"name":"jq","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.1-4ubuntu2"}]}],"versions":["1.8.1-3ubuntu1","1.8.1-4ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"jq","binary_version":"1.8.1-4ubuntu2"},{"binary_version":"1.8.1-4ubuntu2","binary_name":"libjq1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39956.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}