libxml2 before 2.15.4 contains a stack-based buffer overflow in xmlSnprintfElements() (valid.c) due to unsafe strcat usage. The CVSS vector is AV:L/AC:L/PR:N/UI:N, indicating local attack surface with no privileges required; exploitation can corrupt memory and compromise confidentiality/integrity. Upgrade libxml2 to 2.15.4+ to remediate.