Vulnerability · Published Nov 21, 2025 · Assigned by wolfSSL
CVE-2025-11936Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello
Medium 6.3
In plain English
A medium-severity improper input validation in wolfSSL from wolfSSL. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2025-11936 |
| Alpine:v3.24 | wolfssl | 5.8.4-r0 | ALPINE-CVE-2025-11936 |
| Debian:12 | wolfssl | no fix listed | DEBIAN-CVE-2025-11936 |
| Debian:13 | wolfssl | no fix listed | DEBIAN-CVE-2025-11936 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2025-11936 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2025-11936 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2025-11936 |
| Ubuntu:26.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2025-11936 |
| Ubuntu:26.10 | wolfssl | no fix listed | UBUNTU-CVE-2025-11936 |
Affected products (as reported)
Weakness: CWE-20 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L