CVE-2025-11936: wolfssl Input Validation Flaw — Fix

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.

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CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness Type (CWE)

CWE-20 Improper Input Validation

Affected Products

Vendor	Product	Versions
wolfssl	wolfssl	5.8.2 — 5.8.4

References

Advisories & Patches

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

Other References

https://github.com/wolfSSL/wolfssl

Frequently Asked Questions

What is CVE-2025-11936? +

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2025-11936? +

CVE-2025-11936 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-11936? +

CVE-2025-11936 affects products from wolfssl, specifically: wolfssl. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-11936? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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