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OpenAdvisories
Low · 2.3 CVE-2025-11933 EUVD-2025-198525GHSA-g9wx-2hxf-f2rj

DoS Vulnerability in wolfSSL TLS 1.3 CKS Extension

Published Nov 21, 2025 · Updated Dec 8, 2025 · Assigned by wolfSSL

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.

Affected products

VendorProductAffectedFixed
wofSSL wolfSSL — —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 wolfssl No fix yet —
Debian 12 wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 wolfssl No fix yet —
Ubuntu 26.04 LTS wolfssl No fix yet —
Ubuntu 25.10 wolfssl No fix yet —
Ubuntu 24.04 LTS wolfssl No fix yet —
Ubuntu 22.04 LTS wolfssl No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS wolfssl No fix yet —
Ubuntu 18.04 LTS wolfssl No fix yet —
Ubuntu 16.04 LTS wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Alpine v3.24 wolfssl 5.8.4-r0 —
Alpine v3.23 wolfssl 5.9.1-r0 —

References