CVE-2025-12543
⛔ criticalSummary
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 Score
9.6
Critical
EPSS Score
0.1
Exploit Probability
Published Date
2026-01-07
First Seen: 2026-01-17
📊 Relative Risk Intelligence
This CVE is Very High Risk - more severe than 90.2% of all 318,071 vulnerabilities in our database.
#31,299
Top 10% most severe
Severity Percentile
🎯 CISA SSVC Assessment Updated: Jan 8, 2026
🔍 Exploitation Status
None
No known exploits
⚙️ Automatable
NO
Requires human interaction
💥 Technical Impact
Total
Complete system compromise possible
🏆 Discovered By
Red Hat would like to thank Ahmet Artuç for reporting this issue.
SSVC data provided by
CISA
Last Modified
2026-03-18
Source
NVD 🔗
CVSS Vector 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
CWE IDs (Weakness Types)