CVE-2026-8720

wcBlake2bHmacFinal and wcBlake2sHmacFinal 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.

Database specific

{
    "cwe_ids": [
        "CWE-354"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8720.json",
    "cna_assigner": "wolfSSL"
}

References

Affected packages

Git / github.com/wolfssl/wolfssl

Affected ranges

Type

GIT

Repo

https://github.com/wolfssl/wolfssl

Events

Introduced

922d04b3568c6428a9fb905ddee3ef5a68db3108

Fixed

ac01707f552c611fbd135cc723b2682b3e7f80f2

Database specific

{
    "cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "5.9.0"
        },
        {
            "last_affected": "5.9.1"
        },
        {
            "fixed": "5.9.2"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}

Affected versions

v5.*

v5.9.0-stable

v5.9.1-stable

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8720.json"