Medium severity · published Nov 21, 2025
CVE-2025-11933
DoS Vulnerability in wolfSSL TLS 1.3 CKS Extension
6.5
CVSS
0.5%
EPSS
No
On KEV
Description
Improper Input Validation in the TLS 1.3 CKS extension parsing in wolfSSL 5.8.2 and earlier on multiple platforms allows a remote unauthenticated attacker to potentially cause a denial-of-service via a crafted ClientHello message with duplicate CKS extensions.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WO
wolfSSL · wofSSL
3.12.0 before 5.8.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-11933
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-11933
Product
https://github.com/wolfSSL/wolfssl
Issue Tracking
https://github.com/wolfSSL/wolfssl/pull/9132
More from wolfSSL
9.8
CVE-2026-3549
ECH parsing heap buffer overflow
5.5
CVE-2026-3229
Integer Overflow in Certificate Chain Allocation