The XmlSecLibs library as used in the saml2 library in SimpleSAMLphp before 1.15.3 incorrectly verifies signatures on SAML assertions, allow

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• simplesamlphp simplesamlphpbefore 1.15.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2018-6521The sqlauth module in SimpleSAMLphp before 1.15.2 relies on the MySQL utf8 charset, which truncates queries upon encountering four-byte char
  40Plan
• CVE-2017-12868The secureCompare method in lib/SimpleSAML/Utils/Crypto.php in SimpleSAMLphp 1.14.13 and earlier, when used with PHP before 5.6, allows atta
  40Plan
• CVE-2017-12873SimpleSAMLphp 1.7.0 through 1.14.10 might allow attackers to obtain sensitive information, gain unauthorized access, or have unspecified oth
  39Monitor
• CVE-2016-9814The validateSignature method in the SAML2\Utils class in SimpleSAMLphp before 1.14.10 and simplesamlphp/saml2 library before 1.9.1, 1.10.x b
  37Monitor
• CVE-2019-3465Rob Richards XmlSecLibs, all versions prior to v3.0.3, as used for example by SimpleSAMLphp, performed incorrect validation of cryptographic
  36Monitor
• CVE-2018-7711HTTPRedirect.php in the saml2 library in SimpleSAMLphp before 1.15.4 has an incorrect check of return values in the signature validation uti
  32Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const claims = jwt.verify(token, publicKey);

1const claims = jwt.verify(token, publicKey, {2  algorithms: ["RS256"],3  issuer: "https://id.example.com",4  audience: "portal",5});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.