CRITICAL
CVE-2025-12543
Published: January 7, 2026· Updated: Mar 13, 2026
9.6
CVSS v3.1
Official 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.
Technical Analysis
CVE-2025-12543 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
Affected Vendors & Products
Mentioned vendors (from description):
Java
CPE data not yet available in NVD for this CVE.
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
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PacketStorm
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NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Quick Facts
CVE IDCVE-2025-12543
CVSS Score9.6 / 10
SeverityCRITICAL
CISA KEVNo
PublishedJan 7, 2026
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2025-12543 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.