High
undertow — security advisory
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).
- Products
- undertow
- Affected versions
- 1.3.11-1, 1.3.16-1, 1.3.16-1ubuntu0.1~esm1, 1.3.4-1, 1.3.5-1, 1.3.7-1, 1.4.20-1, 1.4.21-1, 1.4.22-1, 1.4.23-1, 1.4.23-2build1, 1.4.23-3, 1.4.23-3ubuntu0.1~esm1, 2.0.23-1, 2.0.27-1, 2.0.28-1, 2.0.29-1, 2.0.29-1ubuntu0.1~esm1, 2.2.12-1, 2.2.13-1, 2.2.14-1, 2.2.16-1, 2.2.16-1ubuntu0.1~esm1, 2.2.8-1, 2.3.18-1, 2.3.18-2, 2.3.20-1, 2.3.20-1ubuntu1, 2.3.8-2, 2.3.8-2ubuntu0.1~esm1
- Fixed versions
- Not specified
- CVEs
- CVE-2023-5379
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 01:05 UTC · Revision 1
Source evidence
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).
osv:UBUNTU-CVE-2023-5379
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
undertow
Fixed versions: Not specified
Complete source record
{
"id": "e2e4cb0c0bd68b42ff7722b6d84b92803086ff735196e6289eb06ff5fcc90281",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2023-5379",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2023-5379",
"summary": "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).",
"evidence": "osv:UBUNTU-CVE-2023-5379",
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"aliases": [
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},
{
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],
"modified": "2026-10-17T12:56:26.678785542Z",
"provider": "osv",
"upstream": [
"CVE-2023-5379"
],
"references": [
"https://ubuntu.com/security/CVE-2023-5379",
"https://bugzilla.redhat.com/show_bug.cgi?id=2242099",
"https://access.redhat.com/security/cve/CVE-2023-5379",
"https://access.redhat.com/errata/RHSA-2023:4509",
"https://www.cve.org/CVERecord?id=CVE-2023-5379"
]
},
"related_cves": [
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"value": "CVE-2023-5379",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 355689,
"published_at": "2023-12-12T22:15:00+00:00"
}