Falko Strenzke

The issue is related to insufficient input validation in the handling of S/MIME messages. Specifically, a crafted message with an inner encryption layer and an outer SignedData layer could be shown as having a valid digital signature, even if the signer did not have access to the encrypted message's contents. This could potentially allow a remote attacker to compromise data integrity.

The issue arises when decoding BER data, potentially leading to an integer overflow. This overflow causes an incorrect length field to be computed. Some API callers may utilize the returned length field, which could be controlled by an attacker, resulting in memory corruption or other failures.