CVE-2011-2516: Off-by-one error in the XML signature feature in Apache XML Security for C++ 1.6.0, as used in Shibboleth b...

Security readout for executives and security teams

CVE-2011-2516 is a remote denial-of-service issue in Apache XML Security for C++ 1.6.0. A specially crafted XML signature using a large RSA key can crash affected software, including Shibboleth before 2.4.3. The sources describe availability impact, not data theft or active exploitation. Exposure is most likely in legacy identity, SSO, or XML-signature-processing services using Apache XML Security for C++ 1.6.0, especially Shibboleth before 2.4.3. The bundle does not identify a complete affected-product list, so dependency inventory is necessary. Address during legacy platform and identity-service patching, with higher urgency for internet-facing Shibboleth or XML signature validation. Business impact is service disruption rather than confirmed compromise, based on the supplied sources. Mitigation focus: Upgrade Shibboleth deployments before 2.4.3 to 2.4.3 or later.; Check Apache Santuario guidance for the fixed XML Security for C++ release.; Apply relevant Debian, Fedora, or vendor package updates..

Prepared

Jun 28, 2026, 00:52 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.