SB2026011002 - Host header injection in Undertow
Published: January 10, 2026
Security Bulletin ID
SB2026011002
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper Neutralization of HTTP Headers for Scripting Syntax (CVE-ID: CVE-2025-12543)
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.