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🛡️ CVE-2026-8720 — wolfssl

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-354 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-8720 is classified as CWE-354: Improper Validation of Integrity Check Value. A checksum or integrity value is not verified properly, so tampered data passes as intact.

Affected software

CVE-2026-8720 is recorded against 1 package.

  • wolfssl (from 5.9.0 up to 5.9.2)

Timeline and source

Published on 25 June 2026 and last revised on 27 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
www.wolfssl.com

Other advisories for this package

wolfssl has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-354: Improper Validation of Integrity Check Value) in other software:

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE CWE-354
Public Exploit ✅ No
Source NVD
Published 2026-06-25
Updated 2026-08-20
Modified 2026-06-27

Affected Packages

Software From version Fixed in
wolfssl 5.9.0 5.9.2

Similar Threats

Site Security Check

Is wolfssl part of your stack?

CVE-2026-8720 is rated CVSS 7.5 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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