What is CVE-2026-6681?

CVE-2026-6681 is a medium-severity vulnerability in Wolfssl, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.3/10. Published 2026-06-25.

How severe is CVE-2026-6681?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Buffer overflow in Wolfssl

CVE-2026-6681

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.

Vulnerability class: Buffer Overflow

EPSS: 0.003 (17.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

Affected products

Wolfssl — versions 3.10.0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)
CWE-787 — Out-of-bounds Write

References

facts@wolfssl.com (Patch, patch, Issue Tracking)
facts@wolfssl.com (Vendor Advisory)

Frequently asked questions

What is CVE-2026-6681?: CVE-2026-6681 is a medium-severity vulnerability in Wolfssl, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.3/10. Published 2026-06-25.
How severe is CVE-2026-6681?: Medium severity. CVSS v3 base score is 5.3 out of 10.