critical9.6
CVE-2025-12543
Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requests
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | io.undertow:undertow-core | = 2.4.0.Alpha1 | none recorded |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Build Of Apache Camel | before 4.14.4 |
| Redhat | Data Grid | Version 8.0 |
| Redhat | Fuse | Version 7.0.0 |
| Redhat | Jboss Enterprise Application Platform | from 8.0 before 8.0.12 from 8.1.0 before 8.1.3 All versions Version 7.0.0 |
| Redhat | Jboss Enterprise Application Platform Expansion Pack | All versions |
| Redhat | Process Automation | Version 7.0 |
| Redhat | Single Sign-On | Version 7.0 |
| Redhat | Undertow | before 2.2.39 from 2.3.0 before 2.3.21 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://access.redhat.com/errata/RHSA-2026:0383
- https://access.redhat.com/errata/RHSA-2026:0384
- https://access.redhat.com/errata/RHSA-2026:0386
- https://access.redhat.com/errata/RHSA-2026:33371
- https://access.redhat.com/errata/RHSA-2026:33372
- https://access.redhat.com/errata/RHSA-2026:3889
- https://access.redhat.com/errata/RHSA-2026:3890
- https://access.redhat.com/errata/RHSA-2026:3891
- https://access.redhat.com/errata/RHSA-2026:3892
- https://access.redhat.com/errata/RHSA-2026:4915
- https://access.redhat.com/errata/RHSA-2026:4916
- https://access.redhat.com/errata/RHSA-2026:4917
- https://access.redhat.com/errata/RHSA-2026:4924
- https://access.redhat.com/errata/RHSA-2026:76128
- https://access.redhat.com/errata/RHSA-2026:76129
- https://access.redhat.com/errata/RHSA-2026:76130
- https://access.redhat.com/errata/RHSA-2026:76132
- https://access.redhat.com/errata/RHSA-2026:76134
- https://access.redhat.com/security/cve/CVE-2025-12543
- https://bugzilla.redhat.com/show_bug.cgi?id=2408784
- https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-12543.json
- https://github.com/advisories/GHSA-j382-5jj3-vw4j
- https://nvd.nist.gov/vuln/detail/CVE-2025-12543
- https://github.com/undertow-io/undertow/pull/1857
- https://github.com/undertow-io/undertow/pull/1860