SB2026011002 - Host header injection in Undertow

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Main Vulnerability Database SB2026011002

SB2026011002 - Host header injection in Undertow

Published: January 10, 2026

Security Bulletin ID SB2026011002
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Neutralization of HTTP Headers for Scripting Syntax (CVE-ID: CVE-2025-12543)

CWE-ID: CWE-644 - Improper Neutralization of HTTP Headers for Scripting Syntax

CVSSv4: 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


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.


Remediation

Install update from vendor's website.

References