Improper input validation in wolfSSL - CVE-2026-5500
Published: April 14, 2026
Vulnerability identifier: #VU125930
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-5500
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication checks.
The vulnerability exists due to improper input validation in wc_PKCS7_DecodeAuthEnvelopedData() when processing the AES-GCM authentication tag length. A remote attacker can truncate the mac field to bypass authentication checks.
A man-in-the-middle can reduce the tag length from 16 bytes to 1 byte.
Affected software
wolfSSL
How to mitigate CVE-2026-5500
Install security update from vendor's website.
wolfSSL - update to 5.9.1