Netty has Unbounded Direct Memory Consumption in its RedisDecoder

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-44890: 0.46% estimated exploitation activity in the next 30 days; percentile 39.99 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary An attacker can cause DoS by sending crafted Redis payloads across multiple connections without \r\n. This exhausts the server's direct memory pool (OutOfDirectMemoryError), preventing legitimate connections from being processed. Details io.netty.handler.codec.redis.RedisDecoder decodes the length of bulk strings and array headers using the decodeLength method. This method reads bytes from the network until it encounters a \n character. However, it does not enforce any maximum length check while buffering the bytes if the \n character is not found. An attacker can exploit this by sending a continuous stream of digits (e.g., $1111...) without ever sending a \n. To cause a true Denial of Service, an attacker must open multiple concurrent connections and distribute the unbounded payloads among them. According to the RESP specification (https://redis.io/docs/latest/develop/reference/protocol-spec/), all parts of the protocol are strictly terminated with \r\n. Furthermore, the…

Published by the source

8 Jun 2026, 19:02 UTC

Last modified by the source

12 Jun 2026, 19:27 UTC

Source last checked

26 Oct 2026, 16:46 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6ghj-frrj-jjj3

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# Patch Next advisory brief: CVE-2026-44890

Advisory: Netty has Unbounded Direct Memory Consumption in its RedisDecoder
IDs: CVE-2026-44890, GHSA-6ghj-frrj-jjj3
Record: https://patchnext.com/advisories/cve-2026-44890 (revision 1, source checked 26 Oct 2026, 16:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.netty:netty-codec-redis 4.2.15.Final, 4.1.135.Final. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.netty:netty-codec-redis: affected >= 4.2.0.Final, <= 4.2.14.Final; <= 4.1.134.Final; fixed in 4.2.15.Final, 4.1.135.Final

## Suggested inspection (read-only)
- Maven io.netty:netty-codec-redis: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.netty:netty-codec-redis.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6ghj-frrj-jjj3 (GitHub-reviewed advisory GHSA-6ghj-frrj-jjj3 lists affected ranges: Maven io.netty:netty-codec-redis >=4.2.0.Final =0 <=4.1.134.Final)

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