CVE-2025-12543
unknown
CVSS v3
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CVSS v4 NEW
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VIR risk
—
Description
Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requests
Predictions
Exploit likelihood
30%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Affected 2 releases
| Version | Status | Fixed in |
|---|---|---|
| sid | Affected | — |
| forky | Affected | — |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| Maven | io.undertow:undertow-core | | |
| Maven | io.undertow:undertow-core | >=2.3.0.Alpha1,<2.3.21.Final | 2.3.21.Final |
| Maven | io.undertow:undertow-core | <2.2.39.Final | 2.2.39.Final |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-12543
- https://github.com/undertow-io/undertow/pull/1860
- https://github.com/undertow-io/undertow/pull/1857
- https://issues.redhat.com/browse/UNDERTOW-2656
- https://github.com/undertow-io/undertow/releases/tag/2.3.21.Final
- https://github.com/undertow-io/undertow/releases/tag/2.2.39.Final
- https://github.com/undertow-io/undertow
- https://bugzilla.redhat.com/show_bug.cgi?id=2408784
- https://access.redhat.com/security/cve/CVE-2025-12543
- https://access.redhat.com/errata/RHSA-2026:4924
- https://access.redhat.com/errata/RHSA-2026:4917
- https://access.redhat.com/errata/RHSA-2026:4916
- https://access.redhat.com/errata/RHSA-2026:4915
- https://access.redhat.com/errata/RHSA-2026:3892
- https://access.redhat.com/errata/RHSA-2026:3891
- https://access.redhat.com/errata/RHSA-2026:3890
- https://access.redhat.com/errata/RHSA-2026:3889
- https://access.redhat.com/errata/RHSA-2026:0386
- https://access.redhat.com/errata/RHSA-2026:0384
- https://access.redhat.com/errata/RHSA-2026:0383
- https://security-tracker.debian.org/tracker/CVE-2025-12543
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.