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9.6
CRITICAL CVSS 3.1
CVE-2025-12543
Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf
Overview
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.

Details
INFO

Published Date :

Jan. 7, 2026, 5:15 p.m.

Last Modified :

March 13, 2026, 2:44 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2025-12543 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Redhat jboss_enterprise_application_platform
2 Redhat single_sign-on
3 Redhat undertow
4 Redhat fuse
5 Redhat data_grid
6 Redhat process_automation
7 Redhat jboss_enterprise_application_platform_expansion_pack
8 Redhat build_of_apache_camel
: Total Affected Vendor : 1 | Products : 8
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 53f830b8-0a3f-465b-8143-3b8a9948e749
CVSS 3.1 CRITICAL [email protected]
CVSS 3.1 CRITICAL [email protected]
Solution
Update Undertow to validate Host headers and prevent cache poisoning and session hijacking.
  • Update Undertow to a patched version.
  • Configure Host header validation.
  • Monitor HTTP request headers.
  • Invalidate relevant caches.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-12543.

URL Resource
https://access.redhat.com/errata/RHSA-2026:0383 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:0384 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:0386 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3889 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3890 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3891 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:3892 Vendor Advisory
https://access.redhat.com/security/cve/CVE-2025-12543 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2408784 Issue Tracking Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-12543 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-12543 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-23: File Content Injection File Content Injection CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-31: Accessing/Intercepting/Modifying HTTP Cookies Accessing/Intercepting/Modifying HTTP Cookies CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-63: Cross-Site Scripting (XSS) Cross-Site Scripting (XSS) CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-73: User-Controlled Filename User-Controlled Filename CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-81: Web Server Logs Tampering Web Server Logs Tampering CAPEC-83: XPath Injection XPath Injection CAPEC-85: AJAX Footprinting AJAX Footprinting CAPEC-88: OS Command Injection OS Command Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-109: Object Relational Mapping Injection Object Relational Mapping Injection CAPEC-110: SQL Injection through SOAP Parameter Tampering SQL Injection through SOAP Parameter Tampering CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-136: LDAP Injection LDAP Injection CAPEC-153: Input Data Manipulation Input Data Manipulation CAPEC-182: Flash Injection Flash Injection CAPEC-209: XSS Using MIME Type Mismatch XSS Using MIME Type Mismatch CAPEC-230: Serialized Data with Nested Payloads Serialized Data with Nested Payloads CAPEC-231: Oversized Serialized Data Payloads Oversized Serialized Data Payloads CAPEC-250: XML Injection XML Injection CAPEC-261: Fuzzing for garnering other adjacent user/sensitive data Fuzzing for garnering other adjacent user/sensitive data CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-473: Signature Spoof Signature Spoof CAPEC-588: DOM-Based XSS DOM-Based XSS CAPEC-664: Server Side Request Forgery Server Side Request Forgery

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-12543 vulnerability anywhere in the article.

  • CybersecurityNews
HPE Telco Service Activator Vulnerability Let Attackers Bypass Access Restrictions

HPE Telco Service Activator Vulnerability Security Bulletin released on February 19, 2026, addresses a remote flaw in HPE Telco Service Activator that could let attackers bypass access restrictions. ... Read more

Published Date: Feb 23, 2026 (2 weeks, 5 days ago)
  • Daily CyberSecurity
Critical Undertow Flaw (CVSS 9.6) Strikes HPE Telco Service Activator

Telecommunications providers rely on complex orchestration tools to keep the world connected, but a newly disclosed vulnerability threatens the core of these operations. A critical security flaw has b ... Read more

Published Date: Feb 23, 2026 (2 weeks, 5 days ago)
  • CybersecurityNews
Undertow HTTP Server Used in Java Apps Vulnerability Allow Attackers to Hijack Sessions

A critical security flaw has been discovered in the Undertow HTTP server core, a widely used component in Java applications such as WildFly and JBoss EAP. The vulnerability, tracked as CVE-2025-12543, ... Read more

Published Date: Jan 09, 2026 (2 months ago)
  • Daily CyberSecurity
Guloader Malware Rides Wave of Fake Performance Reports

Cybercriminals are weaponizing workplace anxiety in a new sophisticated phishing campaign. The AhnLab Security Intelligence Center (ASEC) has issued a warning regarding a malicious operation that leve ... Read more

Published Date: Jan 09, 2026 (2 months ago)
  • Daily CyberSecurity
The 9.6 Crack in Java’s Foundation: Critical Undertow Flaw CVE-2025-12543

A foundational crack has been discovered in the bedrock of the Java web ecosystem. Undertow, the high-performance web server that powers enterprise heavyweights like WildFly and JBoss EAP, has been hi ... Read more

Published Date: Jan 09, 2026 (2 months ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-12543 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Reanalysis by [email protected]

    Mar. 13, 2026

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform:-:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:data_grid:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:* *cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions from (including) 2.3.0 up to (including) 2.3.21 *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions up to (excluding) 2.2.39 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.0 up to (excluding) 8.0.12 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.1.0 up to (excluding) 8.1.3 *cpe:2.3:a:redhat:build_of_apache_camel:*:*:*:*:*:spring_boot:*:* versions up to (excluding) 4.14.4 OR *cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform:-:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:data_grid:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:* *cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions up to (excluding) 2.2.39 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.0 up to (excluding) 8.0.12 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.1.0 up to (excluding) 8.1.3 *cpe:2.3:a:redhat:build_of_apache_camel:*:*:*:*:*:spring_boot:*:* versions up to (excluding) 4.14.4 *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions from (including) 2.3.0 up to (excluding) 2.3.21
  • Initial Analysis by [email protected]

    Mar. 10, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
    Added CPE Configuration OR *cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform:-:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:data_grid:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:* *cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions from (including) 2.3.0 up to (including) 2.3.21 *cpe:2.3:a:redhat:undertow:*:*:*:*:*:*:*:* versions up to (excluding) 2.2.39 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.0 up to (excluding) 8.0.12 *cpe:2.3:a:redhat:jboss_enterprise_application_platform:*:*:*:*:*:*:*:* versions from (including) 8.1.0 up to (excluding) 8.1.3 *cpe:2.3:a:redhat:build_of_apache_camel:*:*:*:*:*:spring_boot:*:* versions up to (excluding) 4.14.4
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:0383 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:0384 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:0386 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:3889 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:3890 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:3891 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:3892 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2025-12543 Types: Vendor Advisory
    Added Reference Type Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2408784 Types: Issue Tracking, Vendor Advisory
  • CVE Modified by [email protected]

    Mar. 05, 2026

    Action Type Old Value New Value
    Added Reference https://access.redhat.com/errata/RHSA-2026:3889
    Added Reference https://access.redhat.com/errata/RHSA-2026:3891
    Added Reference https://access.redhat.com/errata/RHSA-2026:3892
  • CVE Modified by [email protected]

    Mar. 05, 2026

    Action Type Old Value New Value
    Added Reference https://access.redhat.com/errata/RHSA-2026:3890
  • CVE Modified by [email protected]

    Jan. 08, 2026

    Action Type Old Value New Value
    Added Reference https://access.redhat.com/errata/RHSA-2026:0383
  • CVE Modified by [email protected]

    Jan. 08, 2026

    Action Type Old Value New Value
    Added Reference https://access.redhat.com/errata/RHSA-2026:0384
    Added Reference https://access.redhat.com/errata/RHSA-2026:0386
  • New CVE Received by [email protected]

    Jan. 07, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
    Added CWE CWE-20
    Added Reference https://access.redhat.com/security/cve/CVE-2025-12543
    Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2408784
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.6
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact