How severe is GHSA-j382-5jj3-vw4j?

GHSA-j382-5jj3-vw4j has a CVSS score of 9.6/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-j382-5jj3-vw4j?

GHSA-j382-5jj3-vw4j affects the following packages: io.undertow:undertow-core (Maven), io.undertow:undertow-core (Maven), io.undertow:undertow-core (Maven). Ecosystems affected: Maven.

How do I fix GHSA-j382-5jj3-vw4j?

A fix is available for GHSA-j382-5jj3-vw4j; check the affected-versions list above or the advisory for the patched release of io.undertow:undertow-core, then make sure no transitive dependency still pins the vulnerable range.

How do I detect GHSA-j382-5jj3-vw4j in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.undertow:undertow-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-j382-5jj3-vw4j if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-j382-5jj3-vw4j actively exploited in the wild?

No public exploit code has been indexed for GHSA-j382-5jj3-vw4j yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-j382-5jj3-vw4j?

GHSA-j382-5jj3-vw4j has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 71th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-j382-5jj3-vw4j?

GHSA-j382-5jj3-vw4j is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-j382-5jj3-vw4j published, and has it been updated?

GHSA-j382-5jj3-vw4j was published on January 7, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requestsGHSA-j382-5jj3-vw4j

CRITICALFix: undertow-io/undertow#1860

GHSA-j382-5jj3-vw4j is a critical-severity (CVSS 9.6) Improper Input Validation vulnerability in io.undertow:undertow-core. A fix is available for io.undertow:undertow-core — see the affected versions and patch details below.

Also known asCVE-2025-12543

Published

Jan 7, 2026

Updated

Sep 10, 2026

Affected

3 pkgs

Patched

2 / 3

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-j382-5jj3-vw4j.

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs71th percentile — riskier than 71% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

☕io.undertow:undertow-core☕io.undertow:undertow-core☕io.undertow:undertow-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

3 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.undertow:undertow-core`	all versions	No fix
☕Maven	`io.undertow:undertow-core`	≥ 2.3.0.Alpha1&&< 2.3.21.Final	2.3.21.Final`io.undertow:undertow-core:2.3.21.Final`
☕Maven	`io.undertow:undertow-core`	all versions	2.2.39.Final`io.undertow:undertow-core:2.2.39.Final`

Affected Products

8 products · 12 configurations

Application

build of apache camelredhat

< 4.14.4

range

Application

data gridredhat

1 version

8.0

Application

fuseredhat

1 version

7.0.0

Application

jboss enterprise application platformredhat

≥ 8.1.0 && < 8.1.3

1 version

7.0.0

Application

jboss enterprise application platform expansion packredhat

all

Application

process automationredhat

1 version

7.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.undertow:undertow-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
A fix is available for GHSA-j382-5jj3-vw4j; check the affected-versions list above or the advisory for the patched release of io.undertow:undertow-core, then make sure no transitive dependency still pins the vulnerable range.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This vulnerability has an Important severity because it can be remotely exploited without authentication. However, limited user interaction is required for full impact. It could allow attackers to hijack additional accounts, steal credentials, or gain access to internal systems. The issue stems from improper input…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use, applicability, or stability.

Source: Red Hat security advisory for GHSA-j382-5jj3-vw4j (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat build of Apache Camel 4.14.4 for Spring Boot 3.5.11	`undertow-core`	RHSA-2026:3890
Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7	`eap7-undertow-0:1.4.18-21.SP19_redhat_00001.1.ep7.el7`	RHSA-2026:33372
Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7	`eap7-undertow-0:2.0.41-8.SP9_redhat_00001.1.el7eap`	RHSA-2026:33371
Red Hat JBoss Enterprise Application Platform 7.4.24	`io.undertow/undertow-core:2.2.39.Final-redhat-00001`	RHSA-2026:4924
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7	`eap7-undertow-0:2.2.39-1.Final_redhat_00001.1.el7eap`	RHSA-2026:4915
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8	`eap7-undertow-0:2.2.39-1.Final_redhat_00001.1.el8eap`	RHSA-2026:4916
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9	`eap7-undertow-0:2.2.39-1.Final_redhat_00001.1.el9eap`	RHSA-2026:4917
Red Hat JBoss Enterprise Application Platform 8.0	`undertow-core`	RHSA-2026:3892

UbuntuCRITICAL

USN-8144-1Ubuntu

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is GHSA-j382-5jj3-vw4j in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

Undertow HTTP server core doesn't properly validate the Host header in incoming HTTP requestsGHSA-j382-5jj3-vw4j

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is GHSA-j382-5jj3-vw4j in your dependencies?