CVE-2023-5379Network attack vector

Unauthenticated service interruption via oversized AJP headers

Published Dec 12, 2023 · Updated Aug 4, 2026

Undertow denial of service in Red Hat JBoss EAP 7 and Single Sign-On 7 allows remote attackers to interrupt AJP request forwarding. An oversized AJP header makes the backend close TCP without a response, so mod_proxy_cluster marks the worker in error and stops forwarding. Exploitation requires AJP through httpd and max-header-size of 64 KB or less; repeated requests sustain the service interrupt.

CVSS severity7.5
High
EPSS probability1.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Undertow denial of service in Red Hat JBoss EAP 7 and Single Sign-On 7 allows remote attackers to interrupt AJP request forwarding. An oversized AJP header makes the backend close TCP without a response, so mod_proxy_cluster marks the worker in error and stops forwarding. Exploitation requires AJP through httpd and max-header-size of 64 KB or less; repeated requests sustain the service interrupt.

The record

CVE
CVE-2023-5379
Published
Dec 12, 2023
Updated
Aug 4, 2026
Vendor
Red Hat
Product
Red Hat JBoss Enterprise Application Platform 7
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat JBoss Enterprise Application Platform 7Affected versions are unavailable in this record.
Red Hat · Red Hat Single Sign-On 7Affected versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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