{"id":"UBUNTU-CVE-2026-4177","details":"YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitter. The heap overflow occurs when class names exceed the initial 512-byte allocation. The base64 decoder could read past the buffer end on trailing newlines. strtok mutated n-\u003etype_id in place, corrupting shared node data. A memory leak occurred in syck_hdlr_add_anchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return.","modified":"2026-06-30T18:18:05.198340779Z","published":"2026-03-16T23:16:00Z","upstream":["CVE-2026-4177"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-4177"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-4177"},{"type":"REPORT","url":"https://lists.security.metacpan.org/cve-announce/msg/38035745/"},{"type":"REPORT","url":"https://github.com/cpan-authors/YAML-Syck/commit/e8844a31c8cf0052914b198fc784ed4e6b8ae69e"}],"affected":[{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.27-2build2","1.29-1","1.29-1build1","1.29-1ubuntu0.16.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libyaml-syck-perl","binary_version":"1.29-1ubuntu0.16.04.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.29-1build3","1.29-1ubuntu0.18.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.29-1ubuntu0.18.04.1~esm1","binary_name":"libyaml-syck-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.31-1","1.31-1build1","1.31-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.31-1ubuntu0.1~esm1","binary_name":"libyaml-syck-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.34-1build1","1.34-1build2","1.34-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libyaml-syck-perl","binary_version":"1.34-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.34-2","1.34-2build1","1.34-2build2","1.34-2build3","1.34-2ubuntu0.24.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libyaml-syck-perl","binary_version":"1.34-2ubuntu0.24.04.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.34-2build4","1.34-3","1.34-3ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libyaml-syck-perl","binary_version":"1.34-3ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libyaml-syck-perl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.34-3","1.34-4","1.36-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libyaml-syck-perl","binary_version":"1.36-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-4177.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"},{"type":"Ubuntu","score":"medium"}]}