CVE-2026-8720

NameCVE-2026-8720
Descriptionwc_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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1140815

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
wolfssl (PTS)bullseye4.6.0+p1-0+deb11u2vulnerable
bookworm5.5.4-2+deb12u2vulnerable
trixie5.7.2-0.1+deb13u1vulnerable
forky, sid5.9.1-0.1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
wolfsslsource(unstable)(unfixed)1140815

Notes

https://github.com/wolfSSL/wolfssl/pull/10447 (v5.9.2-stable)

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