DEBIAN-CVE-2025-12543

Advisory lineage Upstream: 1 Downstream: 0
Upstream
CVE-2025-12543
Published: 07 Jan 2026, 17:15
Last modified:28 Apr 2026, 20:29

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.6 CRITICAL
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

07 Jan 2026, 17:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:29
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•CRITICAL•Score: 9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected Systems

  • debian•undertow

    all

References (1)