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TI-2026-32225 Aliases CVE-2026-44248GHSA-jfg9-48mv-9qgx

Netty: Resource exhaustion in MqttDecoder

Priority MEDIUM 40CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 4 fixed, 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.

Summary

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00563 47th percentileScored 2026-11-07
Fix Partial netty (netty): 4.2.13.Final, 4.1.133.Finalnetty-codec-mqtt (io.netty): 4.2.13.Final, 4.1.133.Final+1 more productRed Hat: 4 advisoriesRed Hat: 4 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nettynetty4.2.0.Alpha1 to before 4.2.13.Final; before 4.1.133.Final4.2.13.Final, 4.1.133.FinalPatch availableCNA
nettynetty-codec-mqtt4.2.0.Alpha1 to before 4.2.13.Final; before 4.1.133.Final4.2.13.Final, 4.1.133.FinalPatch availableCNA
—io.netty:netty-codec-mqtt (Maven)4.2.0.Alpha1 to before 4.2.13.Final4.2.13.FinalPatch availableGHSA-jfg9-48mv-9qgx
—io.netty:netty-codec-mqtt (Maven)before 4.1.133.Final4.1.133.FinalPatch availableGHSA-jfg9-48mv-9qgx
  • netty Vendornetty Affected 4.2.0.Alpha1 to before 4.2.13.Final; before 4.1.133.Final Fixed in 4.2.13.Final, 4.1.133.Final Patch available CNA
  • netty-codec-mqtt Vendornetty Affected 4.2.0.Alpha1 to before 4.2.13.Final; before 4.1.133.Final Fixed in 4.2.13.Final, 4.1.133.Final Patch available CNA
  • io.netty:netty-codec-mqtt (Maven) Vendor— Affected 4.2.0.Alpha1 to before 4.2.13.Final Fixed in 4.2.13.Final Patch available GHSA-jfg9-48mv-9qgx
  • io.netty:netty-codec-mqtt (Maven) Vendor— Affected before 4.1.133.Final Fixed in 4.1.133.Final Patch available GHSA-jfg9-48mv-9qgx

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*before 4.1.133; 4.2.0 to before 4.2.13Vulnerablenetty
  • cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* Versions before 4.1.133; 4.2.0 to before 4.2.13 Vulnerable ·netty

Remediation

  • Fix · CNA netty (netty) Fixed in 4.2.13.Final, 4.1.133.Final
  • Fix · CNA netty-codec-mqtt (io.netty) Fixed in 4.2.13.Final, 4.1.133.Final
  • Fix · GHSA-jfg9-48mv-9qgx io.netty:netty-codec-mqtt (Maven) Fixed in 4.2.13.Final Advisory →
  • Fix · GHSA-jfg9-48mv-9qgx io.netty:netty-codec-mqtt (Maven) Fixed in 4.1.133.Final Advisory →

Red Hat 4 advisories

  • RHSA-2026:66545 Released 2026-09-10 · Red Hat rating Important
    Red Hat AMQ Broker 7.13.6 release and security update
    • Red Hat AMQ Broker 7.13.6
  • RHSA-2026:66488 Released 2026-09-10 · Red Hat rating Important
    Red Hat AMQ Broker 7.14.1 release and security update
    • Red Hat AMQ Broker 7.14.1
  • RHSA-2026:41951 Released 2026-07-20 · Red Hat rating Important
    Red Hat Data Grid 8.6.2 security update
    • Red Hat Data Grid 8.6.2
Show 1 more Red Hat advisories
  • RHSA-2026:37390 Released 2026-07-09 · Red Hat rating Important
    Red Hat Build of Apache Camel 4.18.1.P1 for Spring Boot release.
    • Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Fuse 7AffectedNo fix planned: Will not fix
Red Hat Process Automation 7AffectedNo fix planned: Will not fix
Red Hat AMQ Broker 7.13.6Fixed RHSA-2026:66545
Red Hat AMQ Broker 7.14.1Fixed RHSA-2026:66488
Red Hat Data Grid 8.6.2Fixed RHSA-2026:41951
Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16Fixed RHSA-2026:37390
Not affected: 3 products
  • Red Hat JBoss Enterprise Application Platform 7
  • Red Hat JBoss Enterprise Application Platform Expansion Pack
  • Red Hat Single Sign-On 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-44248
  2. 2026-10-03 Alias added: GHSA-jfg9-48mv-9qgx
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 2

Other 2

  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2026-30861 Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization CVSS 3.1CRITICAL 9.8
  • TI-2026-30864 Netty: HttpClientCodec response desynchronization CVSS 3.1CRITICAL 9.1
  • TI-2026-30859 Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder) CVSS 3.1CRITICAL 9.1
  • TI-2026-40973 Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks CVSS 3.1CRITICAL 9.1
  • TI-2026-40972 Uncontrolled resource consumption in netty CVSS 3.1HIGH 7.5
See all 92 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences