{"id":"UBUNTU-CVE-2026-39979","details":"jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f.","modified":"2026-06-30T18:16:16.654298341Z","published":"2026-04-13T23:16:00Z","related":["USN-8202-1","USN-8202-2"],"upstream":["CVE-2026-39979"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-39979"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-39979"},{"type":"REPORT","url":"https://github.com/jqlang/jq/security/advisories/GHSA-2hhh-px8h-355p"},{"type":"REPORT","url":"https://github.com/jqlang/jq/commit/2f09060afab23fe9390cce7cb860b10416e1bf5f"},{"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:14.04:LTS","purl":"pkg:deb/ubuntu/jq?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.3-1.1ubuntu1.1+esm4"}]}],"versions":["1.2-8","1.3-1","1.3-1.1ubuntu1","1.3-1.1ubuntu1.1","1.3-1.1ubuntu1.1+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3-1.1ubuntu1.1+esm4","binary_name":"jq"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39979.json"}},{"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-2026-39979.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":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"jq","binary_version":"1.5+dfsg-2ubuntu0.1~esm2"},{"binary_name":"libjq1","binary_version":"1.5+dfsg-2ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39979.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_version":"1.6-1ubuntu0.20.04.1+esm2","binary_name":"jq"},{"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-2026-39979.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":{"availability":"No subscription required","binaries":[{"binary_version":"1.6-2.1ubuntu3.2","binary_name":"jq"},{"binary_name":"libjq1","binary_version":"1.6-2.1ubuntu3.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39979.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_name":"jq","binary_version":"1.7.1-3ubuntu0.24.04.2"},{"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-2026-39979.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":{"binaries":[{"binary_version":"1.8.1-3ubuntu1.1","binary_name":"jq"},{"binary_name":"libjq1","binary_version":"1.8.1-3ubuntu1.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39979.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-2026-39979.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}