CVE-2026-50011: Netty Unbounded Pre-allocation Vulnerability

HIGH
Advisory Identifier: GHSA-5w86-c3rq-vjj7
CVSS 7.5
CWE-400 CWE-770
Published
Advisory Summary

CVE-2026-50011 is a HIGH (CVSS 7.5) unbounded pre-allocation vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Netty libraries in the Maven ecosystem. The issue involves unbounded pre-allocation in redisarrayaggregator from resp array length. Remediation is available by upgrading affected packages to version 4.2.15.Final, 4.1.135.Final.

CVE-2026-50011 at a Glance

CVE Identifier CVE-2026-50011
GHSA Identifier GHSA-5w86-c3rq-vjj7
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Netty
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-2026-50011

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

io.netty:netty-codec-redis fixed: 4.2.15.Final
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-codec-redis</artifactId>
    <version>4.2.15.Final</version>
</dependency>
io.netty:netty-codec-redis fixed: 4.1.135.Final
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-codec-redis</artifactId>
    <version>4.1.135.Final</version>
</dependency>
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 -Dincludes=io.netty

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-50011, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=io.netty

Analyze the terminal output to locate any version of Netty in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.2.15.Final), your application is affected.

Note: The mvn dependency:tree -Dincludes=io.netty 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 CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Netty, 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 RedisArrayAggregator pre-allocates ArrayList with initial capacity equal to the RESP array element count declared in an array header. That count is taken from the wire before the corresponding child messages exist. A small malicious header can claim a huge initial capacity. ### Details The aggregator starts a new aggregation level when it receives an ArrayHeaderRedisMessage. For positive lengths it pushes AggregateState, whose constructor runs `new ArrayList<>(length)`. No configurable maximum is applied in this handler, and the peer does not need to supply the array elements for the backing array allocation to occur. In the same pipeline, RedisDecoder enforces RedisConstants.REDIS_MESSAGE_MAX_LENGTH for bulk string lengths but does not apply that cap to array header lengths. Declared array sizes can therefore be extremely large while still passing decoding, and the aggregator immediately attempts Object[] reservation. io.netty.handler.codec.redis.RedisDecoder#decodeLength io.netty.handler.codec.redis.RedisArrayAggregator#decodeRedisArrayHeader ### Impact Availability / resource exhaustion via unbounded pre-allocation from untrusted RESP array headers.

CVE-2026-50011 Affected Netty Versions

2 component(s)
Fixed Versions:
4.2.15.Final4.1.135.Final
Product / Package Ecosystem Affected Versions Fixed Version
io.netty:netty-codec-redis
Maven
≥ 4.2.0.Final
< 4.2.15.Final
4.2.15.Final
io.netty:netty-codec-redis
Maven
< 4.1.135.Final
4.1.135.Final

References

Frequently Asked Questions

What is CVE-2026-50011?
CVE-2026-50011 is a security vulnerability in Netty involving Unbounded pre-allocation in RedisArrayAggregator from RESP array length under CWE-400: Uncontrolled Resource Consumption.
Which Netty versions are affected?
Affected versions include releases prior to 4.2.15.Final, 4.1.135.Final across affected packages: io.netty:netty-codec-redis.
What version fixes CVE-2026-50011?
Upgrading to 4.2.15.Final, 4.1.135.Final (or the latest patched release for your respective branch) resolves the vulnerability.
Is netty-codec-redis affected?
Yes, io.netty:netty-codec-redis is affected in releases prior to 4.2.15.Final, 4.1.135.Final. Upgrade your dependency to 4.2.15.Final, 4.1.135.Final or later.
What is the CVSS score of CVE-2026-50011?
CVE-2026-50011 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-2026-50011?
CVE-2026-50011 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Maven dependencies for CVE-2026-50011?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=io.netty'. 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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5w86-c3rq-vjj7",
  "modified" : "2026-06-15T20:46:16Z",
  "published" : "2026-06-15T20:46:16Z",
  "aliases" : [ "CVE-2026-50011" ],
  "summary" : "Netty: Unbounded pre-allocation in RedisArrayAggregator from RESP array length",
  "details" : "### Summary\nRedisArrayAggregator pre-allocates ArrayList with initial capacity equal to the RESP array element count declared in an array header. That count is taken from the wire before the corresponding child messages exist. A small malicious header can claim a huge initial capacity.\n\n### Details\nThe aggregator starts a new aggregation level when it receives an ArrayHeaderRedisMessage. For positive lengths it pushes AggregateState, whose constructor runs `new ArrayList<>(length)`. No configurable maximum is applied in this handler, and the peer does not need to supply the array elements for the backing array allocation to occur.\n\nIn the same pipeline, RedisDecoder enforces RedisConstants.REDIS_MESSAGE_MAX_LENGTH for bulk string lengths but does not apply that cap to array header lengths. Declared array sizes can therefore be extremely large while still passing decoding, and the aggregator immediately attempts Object[] reservation.\n\nio.netty.handler.codec.redis.RedisDecoder#decodeLength\nio.netty.handler.codec.redis.RedisArrayAggregator#decodeRedisArrayHeader\n\n### Impact\nAvailability / resource exhaustion via unbounded pre-allocation from untrusted RESP array headers.",
  "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" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.netty:netty-codec-redis"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.2.0.Final"
      }, {
        "fixed" : "4.2.15.Final"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.2.14.Final"
    }
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "io.netty:netty-codec-redis"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.1.135.Final"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.1.134.Final"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/security/advisories/GHSA-5w86-c3rq-vjj7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50011"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/netty/netty"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-15T20:46:16Z",
    "nvd_published_at" : "2026-06-12T16:16:31Z"
  }
}