CVE-2026-8720 (GCVE-0-2026-8720)

Vulnerability from cvelistv5 – Published: 2026-06-25 21:18 – Updated: 2026-06-26 10:35
VLAI?
Title
HMAC-BLAKE2 final discards message when key length exceeds block size
Summary
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.
Severity ?
5.9 (Medium)
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-354 - Improper Validation of Integrity Check Value
Assigner
References
Impacted products
Vendor Product Version
wolfSSL wolfSSL Affected: 5.9.0 , ≤ 5.9.1 (semver)
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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