Observable discrepancy in wolfSSL - CVE-2026-6291
Published: July 1, 2026
Vulnerability identifier: #VU136643
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-6291
CWE-ID: CWE-203
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: wolfSSL
Affected software:
wolfSSL
wolfSSL
Detailed vulnerability description
The vulnerability allows a remote attacker to recover encrypted content encryption keys.
The vulnerability exists due to observable discrepancy in error responses in PKCS#7 KTRI decryption when decrypting PKCS#7 EnvelopedData using RSA PKCS#1 v1.5 key transport. A remote attacker can submit crafted EnvelopedData messages and observe error responses to recover encrypted content encryption keys.
How to mitigate CVE-2026-6291
Install security update from vendor's website.