What’s Vulnerable › Vulnerabilities

CVE-2025-11936: Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello

• Severity: medium (CVSS 5.3 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: 2025-11-21 · updated 2026-10-19
• Weakness: CWE-20

Description

Improper input validation in the TLS 1.3 KeyShareEntry parsing in wolfSSL v5.8.2 on multiple platforms allows a remote unauthenticated attacker to cause a denial-of-service by sending a crafted ClientHello message containing duplicate KeyShareEntry values for the same supported group, leading to excessive CPU and memory consumption during ClientHello processing.

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/9117
• https://github.com/wolfSSL/wolfssl/pull/9117

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