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

🗓️ 26 Jan 2026 00:00:00Reported by Broadcom Security ResponseType

broadcom

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Undertow-core fails to reject Host headers, enabling cache poisoning and SSRF (CVE-2025-12543).

Reporter	Title	Published	Views	Family All 77
IBM Security Bulletins	Security Bulletin: IBM Terracotta is affected by two Undertow vulnerabilities that could allow remote denial of service attacks and Host header manipulation leading to cache poisoning or session hijacking	23 Feb 202619:06	–	ibm
IBM Security Bulletins	Security Bulletin: IBM InfoSphere Information Server is affected by multiple vulnerabilities in Undertow	24 Mar 202619:29	–	ibm
IBM Security Bulletins	Security Bulletin: Improper Host Header Validation in Undertow HTTP Server Enables Cache Poisoning and Session Hijacking affects watsonx.data	9 Apr 202616:52	–	ibm
IBM Security Bulletins	Security Bulletin: DevOps Test Performance contains a vulnerability related to use of the Undertow server core	10 Apr 202614:17	–	ibm
ATTACKERKB	CVE-2025-12543	7 Jan 202616:04	–	attackerkb
Chainguard	CVE-2025-12543 vulnerabilities	27 Jan 202601:17	–	cgr
Circl	CVE-2025-12543	7 Jan 202616:56	–	circl
CNNVD	Red Hat Undertow 安全漏洞	7 Jan 202600:00	–	cnnvd
CVE	CVE-2025-12543	7 Jan 202616:04	–	cve
Cvelist	CVE-2025-12543 Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf	7 Jan 202616:04	–	cvelist

26 Jan 2026 20:34Current

5.8Medium risk

Vulners AI Score5.8

CVSS 3.19.6

EPSS0.0005

SSVC

Undertow-core Host headers cache poisoning server side forgery CVE-2025-12543