CVE-2026-93575: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-fcr3-v77c-x7hx
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CVSS 7.5
Published
Advisory Summary

CVE-2026-93575 is a HIGH (CVSS 7.5) security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2026-93575 at a Glance

CVE Identifier CVE-2026-93575
GHSA Identifier GHSA-fcr3-v77c-x7hx
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-93575

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-93575, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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. #

References

NVD — CVE-2026-93575 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-93575
Software Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-93575
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2536967

Frequently Asked Questions

What is CVE-2026-93575?
CVE-2026-93575 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-93575?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-93575?
CVE-2026-93575 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-93575?
CVE-2026-93575 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-93575?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fcr3-v77c-x7hx",
  "modified" : "2026-09-18T15:32:15Z",
  "published" : "2026-09-18T12:31:20Z",
  "aliases" : [ "CVE-2026-93575" ],
  "details" : "### Summary\nNetty'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.\n\n### Details\nIn `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`).\n\nBy 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.\n\n#",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-93575"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-93575"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2536967"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-18T11:17:22Z"
  }
}