The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.

Affected: Ubuntu:22.04:LTS: libmongocrypt, Ubuntu:24.04:LTS: libmongocrypt, Ubuntu:26.10: libmongocrypt, Ubuntu:26.04:LTS: libmongocrypt

The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.