Is CVE-2026-8720 in the CISA KEV catalog?

No. CVE-2026-8720 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8720?

CVE-2026-8720 has a CVSS v3 base score of 7.5 (Moderate).

What is the EPSS score for CVE-2026-8720?

CVE-2026-8720 has an EPSS score of 0.11% (2th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8720?

Upgrade wolfssl to 5.9.2 or later.

CVE & CISA-KEV Catalog

CVE-2026-8720

MEDIUM

7.5

CVSS v3

NVD

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.

CWE-354

How to fix

Remediation Available

wolfsslNVD

Affected:>= 5.9.0, < 5.9.2Fixed in:5.9.2CVE-2026-8720derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploit Intelligence

0.11%probability of exploitation in 30 days

2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

wolfssl.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-27.