CVE-2026-8720wc_Blake2bHmacFinal and wc_Blake2sHmacFinal discard the message when the key length exceeds the block size, producing a MAC that is independent of the input.
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It affects wolfssl. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-354
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 27, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
wolfssl wolfssl wolfssl:wolfssl | from 5.9.0 before 5.9.2 | NVD |
References
- https://github.com/wolfSSL/wolfssl/pull/10447issue-tracking, patch
- https://www.wolfssl.com/docs/security-vulnerabilities/vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.