CVE-2026-13713: medium-severity vulnerability in TODDR YAML::Syck
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
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.2epss 0.2%
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.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
TODDR · YAML::SyckRelated CVEs — TODDR YAML::Syck
In the same product, most dangerous first.
CVE-2026-57075CRITICALYAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64decEPSS 0.6%CVE-2026-4177CRITICALYAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitterEPSS 0.5%CVE-2026-5089HIGHYAML::Syck versions before 1.38 for Perl has an out-of-bounds readEPSS 0.4%CVE-2025-11683MEDIUMYAML::Syck versions before 1.36 for Perl has missing Null-Terminators which causes Out-of-Bounds Read and potential Information DisclosureEPSS 0.3%CVE-2026-57077HIGHYAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_lenEPSS 0.2%CVE-2026-57076HIGHYAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchorEPSS 0.2%