# Netty: \[Bzip2Decoder\] Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang

Advisory record · `GHSA-558v-64gr-wgg4`

- **Identifiers:** `GHSA-558v-64gr-wgg4` · `CVE-2026-59901`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-835](https://cwe.mitre.org/data/definitions/835.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 22 Jul 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 22 Jul 2026, 21:50 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `io.netty:netty-codec-compression` (Maven): affected `>=4.2.0.Final, <4.2.16.Final`; fixed in `4.2.16.Final`
- `io.netty:netty-codec` (Maven): affected `<4.1.136.Final`; fixed in `4.1.136.Final`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> netty-codec-compression versions 4.2.0.Final up to 4.2.16.Final and netty-codec versions before 4.1.136.Final contain an infinite loop in the Bzip2Decoder run-length decoding. An attacker who can send a malformed bzip2 stream to the decoder can hang the event-loop thread, causing a denial of service. Upgrade netty-codec-compression to 4.2.16.Final or netty-codec to 4.1.136.Final.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.7 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0046, the 40th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:17 UTC: First seen by agentprime
- 31 Oct 2026, 14:17 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-558v-64gr-wgg4)

## Sources

- [GitHub Advisory Database: GHSA-558v-64gr-wgg4](https://github.com/advisories/GHSA-558v-64gr-wgg4)
- [OSV: GHSA-558v-64gr-wgg4](https://osv.dev/vulnerability/GHSA-558v-64gr-wgg4)
- <https://github.com/netty/netty/security/advisories/GHSA-558v-64gr-wgg4>
- <https://github.com/netty/netty>
- <https://github.com/netty/netty/releases/tag/netty-4.1.136.Final>
- <https://github.com/netty/netty/releases/tag/netty-4.2.16.Final>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-558v-64gr-wgg4>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-558v-64gr-wgg4/>. Everything for agents: <https://agentprime.io/llms.txt>.