Is CVE-2026-6681 in the CISA KEV catalog?

No. CVE-2026-6681 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-6681?

CVE-2026-6681 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-6681?

CVE-2026-6681 has an EPSS score of 0.26% (17th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-6681?

Upgrade wolfssl on debian unstable to 5.9.1-0.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-6681

MEDIUM

5.3

CVSS v3

NVD

Description

The PKCS#7 decode path ignores the caller-supplied output buffer size (outputSz), allowing decoded content to be written past the bounds of the provided buffer. This affects wolfSSL 5.9.0 and earlier and was fixed in the 5.9.1 release.

CWE-120Classic Buffer Overflow CWE-787Out-of-bounds Write

How to fix

Remediation Available

wolfsslDebian

Fixed in:5.9.1-0.1CVE-2026-6681

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

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.26%probability of exploitation in 30 days

17thpercentile

Low risk: more likely to be exploited than 17% 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.