CVE-2025-12543

Aliases:GHSA-j382-5jj3-vw4j
Advisory lineage Upstream: 0 Downstream: 10
Modified
Published: 07 Jan 2026, 16:04
Last modified:06 May 2026, 14:33

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.6 CRITICAL
v3.1 (cve.org)
EPSS Score
0.05% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

07 Jan 2026, 16:04
Published
Vulnerability first disclosed
06 May 2026, 14:33
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:L
  • v3.1•CRITICAL•Score: 9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.05%• Percentile: 16%

Techniques & Countermeasures

  • CWE-20•Improper Input Validation

    The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Affected Systems

  • io.undertow•undertow-core

    < 2.3.21.Final | ≥ 2.3.0.Alpha1, < 2.3.21.Final | < 2.2.39.Final

  • redhat•build_of_apache_camel

    < 4.14.4

  • redhat•data_grid

    8.0

  • redhat•fuse

    7.0.0

  • redhat•jboss_enterprise_application_platform

    ≥ 8.0, < 8.0.12 | ≥ 8.1.0, < 8.1.3 | na | 7.0.0

  • redhat•jboss_enterprise_application_platform_expansion_pack

    na

  • redhat•process_automation

    7.0

  • redhat•single_sign-on

    7.0

  • redhat•undertow

    < 2.2.39 | ≥ 2.3.0, < 2.3.21

References (20)