CVE-2026-8720

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/wolfSSL/wolfssl/pull/10447	Issue Tracking Patch
https://www.wolfssl.com/docs/security-vulnerabilities/	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*

History

27 Jun 2026, 19:43

Type	Values Removed	Values Added
First Time		Wolfssl wolfssl Wolfssl
CPE		cpe:2.3:a:wolfssl:wolfssl::::::::
References	~~() https://github.com/wolfSSL/wolfssl/pull/10447 -~~	() https://github.com/wolfSSL/wolfssl/pull/10447 - Issue Tracking, Patch
References	~~() https://www.wolfssl.com/docs/security-vulnerabilities/ -~~	() https://www.wolfssl.com/docs/security-vulnerabilities/ - Vendor Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5

25 Jun 2026, 22:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-25 22:17

Updated : 2026-06-27 19:43

NVD link : CVE-2026-8720

Mitre link : CVE-2026-8720

CVE.ORG link : CVE-2026-8720

JSON object : View

Products Affected

wolfssl

wolfssl

CWE

CWE-354

Improper Validation of Integrity Check Value

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