Undertow
CVE-2023-5379
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource allocation limits
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could exhaust system resources through uncontrolled allocation by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set resource limits, implement rate limiting, validate input sizes.
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as Allocation of Resources Without Limits (CWE-770), which allows attackers to exhaust system resources through uncontrolled allocation. A flaw was found in Undertow. When an AJP request is sent that exceeds the max-header-size attribute in ajp-listener, JBoss EAP is marked in an error state by mod_cluster in httpd, causing JBoss EAP to close the TCP connection without returning an AJP response. This happens because mod_proxy_cluster marks the JBoss EAP instance as an error worker when the TCP connection is closed from the backend after sending the AJP request without receiving an AJP response, and stops forwarding. This issue could allow a malicious user could to repeatedly send requests that exceed the max-header-size, causing a Denial of Service (DoS). Affected products include: Redhat Jboss Enterprise Application Platform, Redhat Single Sign-On, Redhat Undertow.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
A flaw was found in Undertow. When an AJP request is sent that exceeds the max-header-size attribute in ajp-listener, JBoss EAP is marked in an error state by mod_cluster in httpd, causing JBoss EAP to close the TCP connection without returning an AJP response. This happens because mod_proxy_cluster marks the JBoss EAP instance as an error worker when the TCP connection is closed from the backend after sending the AJP request without receiving an AJP response, and stops forwarding. This issue could allow a malicious user could to repeatedly send requests that exceed the max-header-size, causing a Denial of Service (DoS).
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
Directory traversal vulnerability in JBoss Undertow 1.0.x before 1.0.17, 1.1.x before 1.1.0.CR5, and 1.2.x before 1.2.0.
A file inclusion vulnerability was found in the AJP connector enabled with a default AJP configuration port of 8009 in U
A flaw was found in, all under 2.0.20, in the Undertow DEBUG log for io.undertow.request.security. Rated critical severi
A vulnerability was found in Undertow web server before 2.0.21. Rated critical severity (CVSS 9.8), this vulnerability i
Undertow HTTP server (used in WildFly, JBoss EAP) fails to validate Host headers, enabling cache poisoning, internal net
A flaw was found in all undertow-2.x.x SP1 versions prior to undertow-2.0.30.SP1, all undertow-1.x.x and undertow-2.x.x
Undertow, a Java web server used across Red Hat's JBoss Enterprise Application Platform, Fuse, and other middleware prod
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authenticat
A flaw was found in undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authenticat
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authenticat
A flaw was found in Undertow. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authenticat
When a POST request comes through AJP and the request exceeds the max-post-size limit (maxEntitySize), Undertow's AjpSer
GitHub PoC
Exploit-DB