Critical severity9.6OSV Advisory· Published Jan 7, 2026· Updated Aug 19, 2026
CVE-2025-12543
CVE-2025-12543
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
io.undertow:undertow-coreMaven | >= 2.3.0.Alpha1, < 2.3.21.Final | 2.3.21.Final |
io.undertow:undertow-coreMaven | < 2.2.39.Final | 2.2.39.Final |
Affected products
16- Range: 1.0.0.Alpha1, 1.0.0.Alpha10, 1.0.0.Alpha11, …
- cpe:2.3:a:redhat:build_of_apache_camel:*:*:*:*:*:spring_boot:*:*Range: <4.14.4
cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:*+ 2 more
- cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:*range: >=8.0,<8.0.12
- cpe:2.3:a:redhat:jboss_enterprise_application_platform:-:*:*:*:text-only:*:*:*
- cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:*
- cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:*
- cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:*
- cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:*
- osv-coords5 versionspkg:apk/chainguard/wildfly-openjdk-17pkg:apk/chainguard/wildfly-openjdk-21pkg:apk/wolfi/wildfly-openjdk-17pkg:apk/wolfi/wildfly-openjdk-21pkg:maven/io.undertow/undertow-core
< 39.0.0-r0+ 4 more
- (no CPE)range: < 39.0.0-r0
- (no CPE)range: < 39.0.0-r0
- (no CPE)range: < 39.0.0-r0
- (no CPE)range: < 39.0.0-r0
- (no CPE)
Patches
Vulnerability mechanics
References
23- access.redhat.com/errata/RHSA-2026:0383nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:0384nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:0386nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:3889nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:3890nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:3891nvdVendor AdvisoryWEB
- access.redhat.com/errata/RHSA-2026:3892nvdVendor AdvisoryWEB
- access.redhat.com/security/cve/CVE-2025-12543nvdVendor AdvisoryWEB
- bugzilla.redhat.com/show_bug.cginvdIssue TrackingVendor AdvisoryWEB
- github.com/advisories/GHSA-j382-5jj3-vw4jghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2025-12543ghsaADVISORY
- access.redhat.com/errata/RHSA-2026:4915nvdWEB
- access.redhat.com/errata/RHSA-2026:4916nvdWEB
- access.redhat.com/errata/RHSA-2026:4917nvdWEB
- access.redhat.com/errata/RHSA-2026:4924nvdWEB
- github.com/undertow-io/undertow/pull/1857ghsaWEB
- github.com/undertow-io/undertow/pull/1860ghsaWEB
- github.com/undertow-io/undertow/releases/tag/2.2.39.FinalghsaWEB
- github.com/undertow-io/undertow/releases/tag/2.3.21.FinalghsaWEB
- issues.redhat.com/browse/UNDERTOW-2656ghsaWEB
- access.redhat.com/errata/RHSA-2026:33371nvd
- access.redhat.com/errata/RHSA-2026:33372nvd
- security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-12543.jsonnvd
News mentions
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