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Vulnerabilities

Vulnerability · CVE-2023-5379

A flaw was found in Undertow.

Published Dec 12, 2023 · catalog updated Nov 5, 2026 · jboss enterprise application platform

Last checked Nov 9, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2023-5379. EPSS is 1.03%. Act only if a listed version of jboss enterprise application platform is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.03%
Remediation
Advisory link
Affected products
cpe redhat/jboss enterprise application platform · cpe redhat/single sign-on · cpe redhat/undertow

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).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe redhat/jboss enterprise application platform7.0.0
  • cpe redhat/single sign-on7.0
  • cpe redhat/undertowversion unspecified

How to fix CVE-2023-5379

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    Seen in 7.0.0 · 1 other packages on the advisory

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2023-5379. EPSS is 1.03%. Act only if a listed version of jboss enterprise application platform is installed.

Which versions are affected?

Compare what you have installed with redhat/jboss enterprise application platform 7.0.0; redhat/single sign-on 7.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 1.03%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 12, 2023 · NIST NVD

    Detected

    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

  2. Nov 5, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2023-5379

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2023-5379

    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 becau

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 9, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 6, 2026
  • NIST NVDNov 5, 2026