FKIE_CVE-2026-81624
Vulnerability from fkie_nvd - Published: 2026-08-31 09:17 - Updated: 2026-08-31 09:17
Severity
Summary
Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:camel_spring_boot:4"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat build of Apache Camel for Spring Boot 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10"
],
"defaultStatus": "unaffected",
"packageName": "moditect",
"product": "Red Hat Enterprise Linux 10",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
],
"defaultStatus": "unaffected",
"packageName": "pki-core:10.6/resteasy",
"product": "Red Hat Enterprise Linux 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
],
"defaultStatus": "unaffected",
"packageName": "pki-deps:10.6/resteasy",
"product": "Red Hat Enterprise Linux 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9"
],
"defaultStatus": "unaffected",
"packageName": "resteasy",
"product": "Red Hat Enterprise Linux 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:jboss_fuse:7"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat Fuse 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jboss_enterprise_application_platform:7"
],
"defaultStatus": "affected",
"packageName": "jboss-eap-7/eap74-els-openjdk11-openshift-rhel8",
"product": "Red Hat JBoss Enterprise Application Platform 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jboss_enterprise_application_platform:7"
],
"defaultStatus": "affected",
"packageName": "jboss-eap-7/eap74-els-openjdk17-openshift-rhel8",
"product": "Red Hat JBoss Enterprise Application Platform 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jboss_enterprise_application_platform:7"
],
"defaultStatus": "affected",
"packageName": "jboss-eap-7/eap74-els-openjdk8-openshift-rhel8",
"product": "Red Hat JBoss Enterprise Application Platform 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jboss_enterprise_application_platform:7"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat JBoss Enterprise Application Platform 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jboss_enterprise_application_platform:8"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat JBoss Enterprise Application Platform 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"cpes": [
"cpe:/a:redhat:jbosseapxp"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat JBoss Enterprise Application Platform Expansion Pack",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:red_hat_single_sign_on:7"
],
"defaultStatus": "affected",
"packageName": "undertow-core",
"product": "Red Hat Single Sign-On 7",
"vendor": "Red Hat"
}
],
"source": "secalert@redhat.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources."
}
],
"id": "CVE-2026-81624",
"lastModified": "2026-08-31T09:17:03.453",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "secalert@redhat.com",
"type": "Primary"
}
]
},
"published": "2026-08-31T09:17:03.453",
"references": [
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/security/cve/CVE-2026-81624"
},
{
"source": "secalert@redhat.com",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524868"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Received",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-770"
}
],
"source": "secalert@redhat.com",
"type": "Primary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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