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CVE-2026-93575— Io.netty/netty-codec-mqtt: netty: resource exhaustion in mqttdecoder

Quick assessment

Affected
Red Hat Red Hat AMQ Broker 7
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Summary Netty's fix for CVE-2026-44248 is incomplete. The decoder checks if the MQTT packet's exceeds , but fails to validate the against the . An attacker can bypass the size limit by sending a small but an enormous . This forces Netty to buffer and parse mil

CVSS 7.5 · High
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I. Basic Information for CVE-2026-93575

Vulnerability Information
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Vulnerability Title
Io.netty/netty-codec-mqtt: netty: resource exhaustion in mqttdecoder
Source: CVE Program / CVE List V5
Vulnerability Description
### Summary Netty's fix for CVE-2026-44248 is incomplete. The decoder checks if the MQTT packet's `Remaining Length` exceeds `maxBytesInMessage`, but fails to validate the `Properties Length` against the `Remaining Length`. An attacker can bypass the size limit by sending a small `Remaining Length` but an enormous `Properties Length`. This forces Netty to buffer and parse millions of properties, allowing an unauthenticated remote attacker to trigger excessive memory and CPU consumption, leading to OutOfMemoryError. ### Details In `io.netty.handler.codec.mqtt.MqttDecoder`, the `decodeProperties()` helper method reads `totalPropertiesLength` and attempts to parse that many bytes. If the buffer lacks the full length, a `Signal` is thrown. The `catch` block inside `decode()` only enforces `maxBytesInMessage` against `bytesRemainingBeforeVariableHeader` (the packet's `Remaining Length`). By sending a `CONNECT` packet with a small `Remaining Length` but a huge `Properties Length`, the size check passes. `ReplayingDecoder` then buffers data from the network until the huge `Properties Length` is reached, parsing millions of `UserProperty` objects and exhausting CPU and memory. #
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
OWASP 2017年十大分类A9-使用含有已知漏洞的组件
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Red Hat Red Hat AMQ Broker 7 - cpe:/a:redhat:amq_broker:7
Red Hat Red Hat build of Apache Camel for Spring Boot 4 - cpe:/a:redhat:camel_spring_boot:4
Red Hat Red Hat Fuse 7 - cpe:/a:redhat:jboss_fuse:7
Red Hat Red Hat JBoss Enterprise Application Platform 7 - cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat Red Hat JBoss Enterprise Application Platform 7 - cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat Red Hat JBoss Enterprise Application Platform 7 - cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat Red Hat JBoss Enterprise Application Platform 7 - cpe:/a:redhat:jboss_enterprise_application_platform:7
Red Hat Red Hat Single Sign-On 7 - cpe:/a:redhat:red_hat_single_sign_on:7

II. Public POCs for CVE-2026-93575

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III. Intelligence Information for CVE-2026-93575

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Vendor Advisories for CVE-2026-93575 (2)

Same Patch Batch · Red Hat · 2026-09-18 · 37 CVEs total

CVE-2026-93569 8.2 HIGH Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :au
CVE-2026-93565 7.5 HIGH Io.netty/netty-codec-http: netty rtspdecoder method-token smuggling via trailing control b
CVE-2026-89059 7.5 HIGH Resteasy-core: resteasy: iioimageprovider unbounded image decode (decompression-bomb dos)
CVE-2026-93494 7.5 HIGH Io.netty/netty-codec-stomp: netty: bytebuf leak in stompsubframedecoder when a frame body
CVE-2026-87743 7.5 HIGH Quarkus-vertx-http: authorization bypass via path normalization discrepancy in quarkus htt
CVE-2026-93572 7.5 HIGH Io.netty/netty-codec-redis: netty: redisarrayaggregator nested resp headers multiply patch
CVE-2026-93563 7.5 HIGH Io.netty/netty-codec-smtp: netty: unbounded multi-line response accumulation in smtprespon
CVE-2026-93488 7.5 HIGH Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams
CVE-2026-93491 7.5 HIGH Io.netty/netty-codec-http: netty: denial of service via unbounded httpservercodec http/1.1
CVE-2026-93560 7.5 HIGH Io.netty/netty-codec-stomp: netty: stomp codec content-length long-to-int truncation cause
CVE-2026-93558 7.5 HIGH Io.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserver
CVE-2026-93564 7.5 HIGH Io.netty/netty-codec-haproxy: netty: haproxy proxy-v2 nested-tlv grandchild bytebuf refere
CVE-2026-93567 7.5 HIGH Io.netty/netty-codec-http2: http/1 authority-form connect is translated to malformed http/
CVE-2026-93576 7.5 HIGH Io.netty/netty-codec-smtp: netty netty-codec-smtp — smtp command-name field is not crlf-va
CVE-2026-91149 7.5 HIGH Cockpit: cockpit: denial of service via unbounded connection thread spawning
CVE-2026-93568 7.5 HIGH Io.netty/netty-codec-http2: io.netty/netty-codec-http3: netty: http/2 and http/3 extended
CVE-2026-89058 7.4 HIGH Resteasy-core: resteasy: corsfilter reflects arbitrary origin with credentials under wildc
CVE-2026-81627 6.7 MEDIUM Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smra
CVE-2026-93579 6.5 MEDIUM Io.netty/netty-codec-http2: netty: http/2 header field values are not validated by default
CVE-2026-93561 6.5 MEDIUM Io.netty/netty-codec-memcache: netty: memcache binary codec signed/unsigned type mismatch

Showing top 20 of 37 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Red Hat AMQ Broker 7
Same vendor: Red Hat
Same weakness: CWE-1035

V. Comments for CVE-2026-93575

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