Vulnerability · Published Jun 25, 2026 · Assigned by wolfSSL
CVE-2026-6681PKCS#7 decode ignores caller output buffer size, writing past buffer bounds
Low 1.0
In plain English
A low-severity out-of-bounds write in wolfSSL from wolfSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)1.0Low
Exploit odds (30 days)0.4%top 68.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | wolfssl | 5.9.2-r0 | ALPINE-CVE-2026-6681 |
| Debian:12 | wolfssl | 5.5.4-2+deb12u3 | DEBIAN-CVE-2026-6681 |
| Debian:13 | wolfssl | 5.7.2-0.1+deb13u2 | DEBIAN-CVE-2026-6681 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-6681 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-6681 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-6681 |
Affected products (as reported)
Weakness: CWE-787, CWE-120 · Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/U:Clear