Expat Denial of Service via storeAtts() Quadratic Complexity
En bref
Sévérité
HIGH 8.7
EPSS
EPSS 0.74 % · centile 54 (2026-10-27)
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
VulnCheck
Statut NVD
Analyzed
Description
Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options.
