What’s Vulnerable › Vulnerabilities
CVE-2026-5500: Improper Validation of AES-GCM Authentication Tag Length in PKCS#7 Envelope Allows Authentication Bypass
- Severity: medium (CVSS 5.9 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-10 · updated 2026-06-17
- Weakness: CWE-20
Description
wolfSSL's wc_PKCS7_DecodeAuthEnvelopedData() does not properly sanitize the AES-GCM authentication tag length received and has no lower bounds check. A man-in-the-middle can therefore truncate the mac field from 16 bytes to 1 byte, reducing the tag check from 2⁻¹²⁸ to 2⁻⁸.
Affected products
- wolfSSL: through 5.9.0
References
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