# CVE-2021-37137: SnappyFrameDecoder doesn't restrict chunk length any may buffer skippable chunks in an unnecessary way

Source: https://junglewise.ai/threats/cve-2021-37137-snappyframedecoder-doesn-t-restrict-chunk-length-any-may-buffer  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-09-09  
License: CC BY 4.0 with a link back

CVE-2021-37137 · Severity: low · CVSS 3.1 · Published 2021-09-09

SnappyFrameDecoder doesn't restrict chunk length any may buffer skippable chunks in an unnecessary way

Technologies: [io.netty:netty (Maven)](https://junglewise.ai/threats/technologies/io-netty-netty), [io.netty:netty-codec (Maven)](https://junglewise.ai/threats/technologies/io-netty-netty-codec), [org.jboss.netty:netty (Maven)](https://junglewise.ai/threats/technologies/org-jboss-netty-netty). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2021-37137 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-37137 being exploited in the wild.

**How severe is CVE-2021-37137?** Low severity, with a CVSS score of 3.1, published 9 September 2021.

**Which products and versions are affected?** io.netty:netty (Maven) ECOSYSTEM:introduced=0; io.netty:netty-codec (Maven) ECOSYSTEM:introduced=4.0.0,fixed=4.1.68.Final; org.jboss.netty:netty (Maven) ECOSYSTEM:introduced=0.

**Is there a fix for CVE-2021-37137?** Yes. io.netty:netty-codec (Maven): upgrade to 4.1.68.Final or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-37137?** Check whether you run io.netty:netty (Maven), io.netty:netty-codec (Maven) or org.jboss.netty:netty (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- io.netty:netty-codec (Maven): upgrade to 4.1.68.Final or later

  ```sh
  # set io.netty:netty-codec to 4.1.68.Final in your pom.xml or build.gradle
  ```


## Affected products

- io.netty:netty (Maven) ECOSYSTEM:introduced=0
- io.netty:netty-codec (Maven) ECOSYSTEM:introduced=4.0.0,fixed=4.1.68.Final
- org.jboss.netty:netty (Maven) ECOSYSTEM:introduced=0

## Identifiers

- CVE-2021-37137
- GHSA-9vjp-v76f-g363

## Related threats

- [Netty Bzip2Decoder infinite loop denial of service](https://junglewise.ai/threats/cve-2026-59901-netty-bzip2decoder-infinite-loop-denial-of-service)
- [Netty Lz4FrameDecoder resource exhaustion](https://junglewise.ai/threats/cve-2026-42583-netty-lz4framedecoder-resource-exhaustion)
- [Netty's decoders vulnerable to DoS via zip bomb style attack](https://junglewise.ai/threats/cve-2025-58057-netty-s-decoders-vulnerable-to-dos-via-zip-bomb-style-attack)
- [Netty denial of service vulnerability](https://junglewise.ai/threats/cve-2014-0193-netty-denial-of-service-vulnerability)
- [HTTP request smuggling in netty](https://junglewise.ai/threats/cve-2021-43797-http-request-smuggling-in-netty)