CVE-2025-12543

9.6 CRITICAL
Published: January 07, 2026 Modified: March 18, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:0383
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:0384
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:0386
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3889
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3890
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3891
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3892
Source: secalert@redhat.com
Vendor Advisory
https://access.redhat.com/security/cve/CVE-2025-12543
Source: secalert@redhat.com
Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2408784
Source: secalert@redhat.com
Issue Tracking Vendor Advisory

13 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.6 / 10.0
EPSS (Exploit Probability)
0.0%
14th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

redhat