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

Published 2026-06-25 · last modified 2026-06-27.

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.

EPSS exploit prediction

EPSS: 0.004 (29.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Wolfssl — versions 3.10.0

Weakness classification (CWE)

References

github.com/wolfSSL/wolfssl/pull/10116 (Patch, patch, Issue Tracking)
www.wolfssl.com/docs/security-vulnerabilities/ (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.