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Fencer Vulns
high 7.5

CVE-2026-93558 json

Io.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserverextensionhandler leads to denial of service

published 2026-09-18 51 d ago modified 2026-11-06 2 d ago also EUVD-2026-82929

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Build of Apache Camel 3.33.3.SP2 4.1.138.Final-redhat-00001
  • Red Hat Red Hat build of Keycloak 26.4 26.4-29, 26.4-30, 26.4.17-2
  • Red Hat Red Hat build of Keycloak 26.6 26.6-24, 26.6.8-2
  • netty-tcnative SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.0.84-150200.3.51.1
  • netty SLE Module for Package Hub 15 SP7 4.1.138-150200.4.56.1

suse advisories SUSE-SU-2026:4391-1

  • netty openSUSE Tumbleweed 4.1.138-1.1

opensuse advisories openSUSE-SU-2026:11882-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-93558 updated cvss 7.5

io.netty/netty-codec-http: Netty: Unbounded Per-Connection Queue Growth in WebSocketServerExtensionHandler Leads to Denial of Service

  • Red Hat AMQ Broker 7 netty-codec-http 4.1.137.Final-redhat-00001 Red Hat AMQ Clients netty-codec-http 4.1.137.Final-redhat-00001 Red Hat build of Apache Camel 4 for Quarkus 3 netty-codec-http 4.1.137.Final-redhat-00001 Red Hat build of Apache Camel for Spring Boot 4 netty-codec-http 4.1.137.Final-redhat-00001 Red Hat build of Apicurio Registry 3 netty-codec-http 4.1.137.Final-redhat-00001 Red Hat Data Grid 8 netty-codec-http 4.1.137.Final-redhat-00001
    affected: workaround, no fix available “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.”
  • Red Hat Fuse 7 netty-codec-http 4.1.137.Final-redhat-00001 Red Hat JBoss Enterprise Application Platform 7 netty-codec-http 4.1.137.Final-redhat-00001
    affected: workaround, no fix planned “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.”
  • Red Hat Single Sign-On 7 netty-codec-http 4.1.137.Final-redhat-00001
    affected: workaround, no fix available “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.”
  • Red Hat Build of Apache Camel 3.33.3.SP2 netty-codec-http 4.1.138.Final-redhat-00001
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:70257
  • Red Hat Build of Debezium 3.6
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:83612
  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-29, rhbk/keycloak-rhel9-operator 26.4-30, rhbk/keycloak-operator-bundle 26.4.17-2
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:95760
  • Red Hat build of Keycloak 26.4.17
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:95759
  • Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-24, rhbk/keycloak-rhel9-operator 26.6-24, rhbk/keycloak-operator-bundle 26.6.8-2
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:95762
show 5 more
  • Red Hat build of Keycloak 26.6.8
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:95761
  • Red Hat build of Quarkus 3.27.5.SP2
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:69470
  • Red Hat build of Quarkus 3.33.3.SP2
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:69440
  • Red Hat JBoss Enterprise Application Platform 8.1
    fixed: vendor fix “See https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc for fixed versions and remediation guidance.” RHSA-2026:95887
  • Red Hat Build of Apache Camel 3.33.3.SP2 jimfs 1.1, jna 5.8.0, bcel 6.7.0, gax 2.74.1, icu4j 78.2, joni 2.2.6, +1616 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
51 d ago

Exploit prediction

1.22% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2536932 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Build of Apache Camel 3.33.3.SP2
  • Red Hat Red Hat Build of Debezium 3.6
  • Red Hat Red Hat build of Keycloak 26.4
  • Red Hat Red Hat build of Keycloak 26.4.17
  • Red Hat Red Hat build of Keycloak 26.6
  • Red Hat Red Hat build of Keycloak 26.6.8
  • Red Hat Red Hat build of Quarkus 3.27.5.SP2
  • Red Hat Red Hat build of Quarkus 3.33.3.SP2
  • Red Hat Red Hat JBoss Enterprise Application Platform 8.1
  • Red Hat Red Hat AMQ Broker 7
  • Red Hat Red Hat AMQ Clients
  • Red Hat Red Hat build of Apache Camel 4 for Quarkus 3
  • Red Hat Red Hat build of Apache Camel for Spring Boot 4
  • Red Hat Red Hat build of Apicurio Registry 3
  • Red Hat Red Hat Data Grid 8
  • Red Hat Red Hat Fuse 7
  • Red Hat Red Hat JBoss Enterprise Application Platform 7
  • Red Hat Red Hat Single Sign-On 7

Classification

Weakness
  • CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.