Public vulnerability disclosure
CVE-2026-93558
Io.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserverextensionhandler leads to denial of service
publishedCWE-1035
A flaw was found in Netty's WebSocketServerExtensionHandler. A remote, unauthenticated attacker can exploit this vulnerability by using HTTP/1.1 pipelining to send requests faster than the application can respond. This leads to an unbounded growth of a per-connection queue, consuming excessive memory. Eventually, this can cause the Java Virtual Machine (JVM) to exhaust its heap, resulting in a Denial of Service (DoS) for the affected server.
Technical severity7.5 highCVSS 3.1 · CNA: redhat
Published2026-09-18Source updated 2026-11-06
Collected2026-11-063 attributed sources
Fixes and workarounds
Workaround
See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Build of Apache Camel 3.33.3.SP2 Red Hat io.netty/netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
≥ 4.1.138.Final-redhat-00001; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Build of Debezium 3.6 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat build of Keycloak 26.4 Red Hat rhbk/keycloak-operator-bundle
https://catalog.redhat.com/software/containers/ |
≥ 26.4.17-2; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.4 Red Hat rhbk/keycloak-rhel9
https://catalog.redhat.com/software/containers/ |
≥ 26.4-29; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.4 Red Hat rhbk/keycloak-rhel9-operator
https://catalog.redhat.com/software/containers/ |
≥ 26.4-30; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.4.17 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat build of Keycloak 26.6 Red Hat rhbk/keycloak-operator-bundle
https://catalog.redhat.com/software/containers/ |
≥ 26.6.8-2; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.6 Red Hat rhbk/keycloak-rhel9
https://catalog.redhat.com/software/containers/ |
≥ 26.6-24; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.6 Red Hat rhbk/keycloak-rhel9-operator
https://catalog.redhat.com/software/containers/ |
≥ 26.6-24; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat build of Keycloak 26.6.8 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat build of Quarkus 3.27.5.SP2 Red Hat netty-codec-http
https://access.redhat.com/jbossnetwork/restricted/listSoftware.html |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat build of Quarkus 3.33.3.SP2 Red Hat netty-codec-http
https://access.redhat.com/jbossnetwork/restricted/listSoftware.html |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat JBoss Enterprise Application Platform 8.1 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat AMQ Broker 7 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat AMQ Clients Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat build of Apache Camel 4 for Quarkus 3 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat build of Apache Camel for Spring Boot 4 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat build of Apicurio Registry 3 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Data Grid 8 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Fuse 7 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat JBoss Enterprise Application Platform 7 Red Hat netty-codec-http
https://access.redhat.com/jbossnetwork/restricted/listSoftware.html |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Single Sign-On 7 Red Hat netty-codec-http
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD: [email protected] |
Exploit evidence
- https://bugzilla.redhat.com/show_bug.cgi?id=2536932
exploit · ADP: CISA-ADP
References
- https://access.redhat.com/errata/RHSA-2026:69440CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:69470CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:70257CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:83612CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:95759CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:95760CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:95761CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:95762CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:95887CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-93558CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2536932CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2536932ADP: CISA-ADP · exploit
- https://access.redhat.com/errata/RHSA-2026:69440[email protected]
- https://access.redhat.com/errata/RHSA-2026:69470[email protected]
- https://access.redhat.com/errata/RHSA-2026:70257[email protected]
- https://access.redhat.com/errata/RHSA-2026:83612[email protected]
- https://access.redhat.com/errata/RHSA-2026:95760[email protected]
- https://access.redhat.com/errata/RHSA-2026:95761[email protected]
- https://access.redhat.com/security/cve/CVE-2026-93558[email protected]
- https://bugzilla.redhat.com/show_bug.cgi?id=2536932[email protected]
- https://bugzilla.redhat.com/show_bug.cgi?id=2536932134c704f-9b21-4f2e-91b3-4a467353bcc0
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