#VU121145 Improper Neutralization of HTTP Headers for Scripting Syntax in Undertow - CVE-2025-12543

Vulnerability identifier: #VU121145

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-12543

CWE-ID: CWE-644

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Undertow
Server applications / Web servers

Vendor: Red Hat Inc.

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to improper input validation when processing HTTP requests. A remote non-authenticated attacker can send a specially crafted HTTP request with an arbitrary Host header that will be accepted by the application.

Successful exploitation of the vulnerability may allow an attacker to perform cross-site scripting, cache poisoning or session hijacking attacks.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Undertow: All versions

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=2408784

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Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?