Out-of-bounds Read in Wolfssl

CVE-2026-4159

1-byte OOB heap read in wc_PKCS7_DecodeEnvelopedData via zero-length encrypted content. A vulnerability existed in wolfSSL 5.8.4 and earlier, where a 1-byte out-of-bounds heap read in wc_PKCS7_DecodeEnvelopedData could be triggered by a crafted CMS EnvelopedData message with zero-length encrypted content. Note that PKCS7 support is disabled by default.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.001 (2.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-4159: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-4159?
CVE-2026-4159 is a low-severity vulnerability in Wolfssl, classified under Out-of-bounds Read. CVSS score: 3.3/10. Published 2026-03-19.
How severe is CVE-2026-4159?
Low severity. CVSS v3 base score is 3.3 out of 10.