#VU112160 Allocation of Resources Without Limits or Throttling in Undertow - CVE-2023-5379

Vulnerability identifier: #VU112160

Vulnerability risk: Medium

CVSSv4.0: 6.6 [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: Network

Exploit availability: No

Vulnerable software:
Undertow
Server applications / Web servers

Vendor: Red Hat Inc.

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.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Undertow: - - 2.3.18

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External links
https://access.redhat.com/errata/RHSA-2023:4509
https://access.redhat.com/errata/RHSA-2023:4509
https://access.redhat.com/errata/RHSA-2025:9582
https://access.redhat.com/errata/RHSA-2025:9583
https://access.redhat.com/security/cve/CVE-2023-5379
https://access.redhat.com/security/cve/CVE-2023-5379
https://bugzilla.redhat.com/show_bug.cgi?id=2242099
https://bugzilla.redhat.com/show_bug.cgi?id=2242099

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.