A NULL pointer can be dereferenced when signatures are being verified on
PKCS7 signed or signedAndEnveloped data. In case the hash algorithm used
for the signature is known to the OpenSSL library but the implementation of
the hash algorithm is not available the digest initialization will fail.
There is a missing check for the return value from the initialization
function which later leads to invalid usage of the digest API most likely
leading to a crash. The unavailability of an algorithm can be caused by
using FIPS enabled configuration of providers or more commonly by not
loading the legacy provider. PKCS7 data is processed by the SMIME library
calls and also by the time stamp (TS) library calls. The TLS implementation
in OpenSSL does not call these functions however third party applications
would be affected if they call these functions to verify signatures on
untrusted data.
#### Notes
Author| Note
—|—
[mdeslaur]() | 3.x onlyRead More