Allocation of Resources Without Limits or Throttling in Undertow - CVE-2023-5379
Published: July 3, 2025
Vulnerability identifier: #VU112160
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2023-5379
CWE-ID: CWE-770
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Red Hat Inc.
Affected software:
Undertow
Undertow
Detailed vulnerability description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability occurs 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. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.
How to mitigate CVE-2023-5379
Install updates from vendor's website.