YAML::Syck versions before 1.47 contain a heap use‑after‑free that occurs when an anchor name is reused as an anchors‑table key in syck_hdlr_add_anchor. When the node carrying that anchor is freed, the shared key is also freed, and a subsequent anchor redefinition uses st_strcmp to compare against freed memory, resulting in a use‑after‑free that can corrupt heap memory. The CVE description states that this flaw is reached on the default Load path when an application loads untrusted YAML documents. The flaw is thus a memory‑corruption vulnerability without an explicit claim of arbitrary code execution.

Vendor Toddr provides the YAML::Syck library. All releases prior to version 1.47 are affected. Applications that embed Perl with YAML::Syck below this version and that accept untrusted YAML input at runtime are vulnerable. Based on the description, the vulnerability is triggered when an application uses the default Load or LoadFile path to parse untrusted YAML.

The CVSS score of 7.8 classifies this issue as high severity. The EPSS score is less than 1 %, indicating a very low current exploitation probability in the wild. The vulnerability is not listed in the CISA KEV catalog. Based on the description, the likely attack vector is an application supplying a malicious YAML document that redefines an anchor, triggering the use‑after‑free and potentially corrupting program memory.