In Bouncy Castle JCE Provider version 1.55 and earlier the DSA does not fully validate ASN.1 encoding of signature on verification. It is possible to inject extra elements in the sequence making up the signature and still have it validate, which in some cases may allow the introduction of 'invisible' data into a signed structure.

Lasso all versions prior to 2.7.0 has improper verification of a cryptographic signature.

bubble fireworks is an open source java package relating to Spring Framework. In bubble fireworks before version 2021.BUILD-SNAPSHOT there is a vulnerability in which the package did not properly verify the signature of JSON Web Tokens. This allows to forgery of valid JWTs.

phpseclib before 2.0.31 and 3.x before 3.0.7 mishandles RSA PKCS#1 v1.5 signature verification.

Enigmail before 2.0.11 allows PGP signature spoofing: for an inline PGP message, an attacker can cause the product to display a "correctly signed" message indication, but display different unauthenticated text.

LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.5.

The XmlSecLibs library as used in the saml2 library in SimpleSAMLphp before 1.15.3 incorrectly verifies signatures on SAML assertions, allowing a remote attacker to construct a crafted SAML assertion on behalf of an Identity Provider that would pass as cryptographically valid, thereby allowing them to impersonate a user from that Identity Provider, aka a key confusion issue.

Duo Network Gateway 1.2.9 and earlier may incorrectly utilize the results of XML DOM traversal and canonicalization APIs in such a way that an attacker may be able to manipulate the SAML data without invalidating the cryptographic signature, allowing the attack to potentially bypass authentication to SAML service providers.

Wizkunde SAMLBase may incorrectly utilize the results of XML DOM traversal and canonicalization APIs in such a way that an attacker may be able to manipulate the SAML data without invalidating the cryptographic signature, allowing the attack to potentially bypass authentication to SAML service providers.

Hyperledger Iroha versions v1.0_beta and v1.0.0_beta-1 are vulnerable to transaction and block signature verification bypass in the transaction and block validator allowing a single node to sign a transaction and/or block multiple times, each with a random nonce, and have other validating nodes accept them as separate valid signatures.

SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 does not validate the signatures of any SAML assertions it receives. Any actor with network access to the deployment could impersonate users when SAML is the authentication method. (Only versions after 2.0.5a are affected.)

Union Pay up to 3.3.12, for iOS mobile apps, contains a CWE-347: Improper Verification of Cryptographic Signature vulnerability, allows attackers to shop for free in merchants' websites and mobile apps, via a crafted authentication code (MAC) which is generated based on a secret key which is NULL.