CVE-2026-8720

Name of the Vulnerable Software and Affected Versions wolfSSL version 5.9.0

Description The functions wc Blake2bHmacFinal() and wc Blake2sHmacFinal() discard the message when the key length exceeds the block size. This occurs because the key-hashing branch reinitializes the running hash state, which discards the accumulated message data. Consequently, the resulting Message Authentication Code (MAC)—a short piece of data used to authenticate a message—depends only on the key and not on the message being authenticated.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.