CVE-2025-12543 - Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf

CVE-2025-12543 - Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf

https://cvefeed.io/rssfeed/latest.atom / Wed, 01/07/2026 - 19:56
CVE ID : CVE-2025-12543
Published : Jan. 7, 2026, 4:04 p.m. | 55 minutes ago
Description : A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.
Severity: 9.6 | CRITICAL
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Kenya Education Network CERT(KENET-CERT) is a Cybersecurity Emergency Response Team and Co-ordination Center operated by the National Research and Education Network of Kenya. KENET-CERT coordination center promotes awareness on cybersecurity incidences as well as coordinates and assists member institutions in responding effectively to cyber security threats and incidences. KENET-CERT works closely with Kenya's National CIRT coordination center (CIRT/CC) as a sector CIRT for the academic institutions. KENET promotes use of ICT in Teaching, Learning and Research in Higher Education Institutions in Kenya. KENET aims to interconnect all the Universities, Tertiary and Research Institutions in Kenya by setting up a cost effective and sustainable private network with high speed access to the global Internet. KENET also facilitates electronic communication among students and faculties in member institutions, share learning and teaching resources by collaboration in Research and Development of Educational content.