{"id":"DEBIAN-CVE-2026-13713","details":"YAML::Syck versions before 1.47 for Perl allow a use-after-free and double-free via an anchor node freed while still on the parser value stack.  In the bundled libsyck, when an anchor name is redefined or removed, syck_hdlr_add_anchor and syck_hdlr_remove_anchor free the node stored under that name with syck_free_node. That node can still be live on the parser's value stack, so syck_hdlr_add_node reaches it again and frees it a second time. On a normal build the 48-byte node chunk is freed twice and the interpreter aborts. Anchors need no special flags, so this is reached on the default Load path, and a 7-byte document that redefines an anchor triggers it.  Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor mid-parse crashes the interpreter, a denial of service.","modified":"2026-09-14T17:01:59.359169371Z","published":"2026-07-16T22:16:59.640Z","upstream":["CVE-2026-13713"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-13713"}],"affected":[{"package":{"name":"libyaml-syck-perl","ecosystem":"Debian:12","purl":"pkg:deb/debian/libyaml-syck-perl?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.34-2+deb12u3"}]}],"versions":["1.34-2","1.34-2+deb12u1","1.34-2+deb12u2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13713.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Debian:13","purl":"pkg:deb/debian/libyaml-syck-perl?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.34-2+deb13u3"}]}],"versions":["1.34-2","1.34-2+deb13u1","1.34-2+deb13u2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13713.json"}},{"package":{"name":"libyaml-syck-perl","ecosystem":"Debian:14","purl":"pkg:deb/debian/libyaml-syck-perl?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.47-1"}]}],"versions":["1.34-2","1.34-3","1.34-4","1.36-1","1.36-2","1.36-3"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-13713.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}