October 7, 2026

CVE Watchtower

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CVE-2025-12543NVD

Vulnerability Summary

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.
Severity Level
CRITICAL(9.6)
Published Date
Jan 7, 2026
Last Modified
Oct 6, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
1.33%Probability
Root Weakness (CWE)
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.
CVSS v3.1 Base Metrics — Score 9.6 (CRITICAL)
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityLow

Affected & Patched Versions

Affected Versions
  • Redhat Build Of Apache Camel < 4.14.4
  • Redhat Data Grid
  • Redhat Fuse
  • Redhat Jboss Enterprise Application Platform >= 8.0 and < 8.0.12
  • Redhat Jboss Enterprise Application Platform >= 8.1.0 and < 8.1.3
  • Redhat Jboss Enterprise Application Platform
  • Redhat Jboss Enterprise Application Platform Expansion Pack
  • Redhat Process Automation
  • Redhat Single Sign-on
  • Redhat Undertow < 2.2.39
  • Redhat Undertow >= 2.3.0 and < 2.3.21
Patched Versions
  • Redhat Build Of Apache Camel 4.14.4
  • Redhat Jboss Enterprise Application Platform 8.0.12
  • Redhat Jboss Enterprise Application Platform 8.1.3
  • Redhat Undertow 2.2.39
  • Redhat Undertow 2.3.21
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🎁7-Day Free Trial — Try Pro or Team, no card required.
📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
📈EPSS Spike Alerts — Catch rising risk before it peaks.
🎯Custom EPSS/CVSS — Filter noise, focus on risk.
🛡️Exploit Intel — A 2nd confirmed-exploit signal beyond KEV.
🐙GitHub Issues — Auto-tracked, no duplicates.
📬Weekly Digest — One clean summary, not inbox spam.
🏷️Watchlist Groups — Tag alerts by team (Infra/AppSec/SOC).
💬Webhooks — Slack & Teams integration.
🔀Smart Routing — Critical alerts to one channel, rest to another.
🚫Ad-Free — Uninterrupted experience.

External References