Skip to content
CVE PROGRAM SOURCE RECORD5.9 Medium

CVE-2026-8720

HMAC-BLAKE2 final discards message when key length exceeds block size

Description

wc_Blake2bHmacFinal and wc_Blake2sHmacFinal discard the message when the key length exceeds the block size, producing a MAC that is independent of the input. When the supplied key is longer than the BLAKE2 block size the key-hashing branch reinitialized the running hash state, discarding the accumulated message data, so the resulting MAC depended only on the key and not on the message being authenticated. This bug is specific to the HMAC-BLAKE2 APIs that were added in wolfSSL version 5.9.0.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

wolfSSL wolfSSL

Default version status: unaffected

  • 5.9.0 to ≤ 5.9.1affected

References