CVE Tools
Sign in

CVE-2026-8720

HMAC-BLAKE2 final discards message when key length exceeds block size

Published: Jun 25, 2026Updated: Jun 27, 2026 Sources: CVE List NVDCWE-354
7.5HIGH
NVD MITRE
EPSS Score
0.1%
Top 98.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-354

Affected Products

wolfSSL
oss-projectaka wolfmqtt, wolfssh
wolfSSLLibraryLibrary
OSS Libraries / generic-library
and 1 more affected products View all →

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-8720?We can run the check for you — a free external exposure review, no install. Check my exposure

References

https://github.com/wolfSSL/wolfssl/pull/10447
github.com
https://www.wolfssl.com/docs/security-vulnerabilities/
wolfssl.com

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-8720 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows