What’s Vulnerable › Vulnerabilities

CVE-2025-11934: Improper Validation of Signature Algorithm Used in TLS 1.3 CertificateVerify

• Severity: low (CVSS 2.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-11-21 · updated 2026-10-19
• Weakness: CWE-20

Description

Improper input validation in the TLS 1.3 CertificateVerify signature algorithm negotiation in wolfSSL 5.8.2 and earlier on multiple platforms allows for downgrading the signature algorithm used. For example when a client sends ECDSA P521 as the supported signature algorithm the server previously could respond as ECDSA P256 being the accepted signature algorithm and the connection would continue with using ECDSA P256, if the client supports ECDSA P256.

Affected products

• wolfSSL: from 5.8.2 before 5.8.4 — fixed in 5.8.4

How to fix

Upgrade to a fixed version: wolfSSL 5.8.4. Check the vendor advisory for mitigations.

References

• https://github.com/wolfSSL/wolfssl
• https://github.com/wolfSSL/wolfssl/pull/9113
• https://github.com/wolfSSL/wolfssl/pull/9113

Get alerted when CVE-2025-11934 or the next vulnerability affects your stack