SAML signature verification bugs are a common issue due to XML Digital Signatures (XML DSIG) fragility and frequent mishandling, leading to real-world vulnerabilities in widely used libraries. Signature validation is hard to get right because of reference confusion, canonicalization mismatch, signature wrapping attacks, and broken or missing schema validation issues. To validate SAML assertions securely, developers should ensure strict reference validation, resolve canonicalization awareness, schema validation, tie verification to usage, use trusted libraries but check them for vulnerabilities, and stay up-to-date with library updates and security advisories. Despite the rise of OIDC and modern identity protocols, SAML remains deeply embedded in enterprise identity scenarios.