# io.netty:netty-codec (Maven) vulnerabilities

5 known vulnerabilities (2 high, 1 medium), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: 4.2.20.Final (Nov 2, 2026): no advisory affects it
- Newest unaffected release: 4.2.20.Final (Nov 2, 2026), the latest release
- Dependents: 61
- Releases: 267 since 4.0.0.Final (Jul 15, 2013)
- Registry: https://central.sonatype.com/artifact/io.netty/netty-codec
- Releases read: Nov 8, 2026

## Version timeline

Affected versions per advisory, in version order:

- CVE-2026-59901: 4.0.0.Alpha1 to 4.1.135.Final (4.1.136.Final is outside it)
- CVE-2026-42583: 4.0.0.Alpha1 to 4.1.132.Final (4.1.133.Final is outside it)
- CVE-2025-58057: 4.0.0.Alpha1 to 4.1.124.Final (4.1.125.Final is outside it)
- CVE-2021-37137: 4.0.0.Final to 4.1.67.Final (4.1.68.Final is outside it)
- CVE-2021-37136: 4.0.0.Alpha1 to 4.1.67.Final (4.1.68.Final is outside it)

## Advisories (5)

### [CVE-2026-59901](https://cve.now/CVE-2026-59901): Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang

- Severity: High 8.7
- Published: Jul 29, 2026
- Affected: fixed in 4.1.136.Final.
- Fixed in 4.1.136.Final (released Jul 8, 2026, 21 days before disclosure).
- The latest release, 4.2.20.Final, is not affected.

### [CVE-2026-42583](https://cve.now/CVE-2026-42583): Netty: Lz4FrameDecoder resource exhaustion

- Severity: High 7.5
- Published: May 13, 2026
- Affected: fixed in 4.1.133.Final.
- Fixed in 4.1.133.Final (released May 5, 2026, 8 days before disclosure).
- The latest release, 4.2.20.Final, is not affected.

### [CVE-2025-58057](https://cve.now/CVE-2025-58057): Netty's BrotliDecoder is vulnerable to DoS via zip bomb style attack

- Severity: Medium 6.9
- Published: Sep 3, 2025
- Affected: fixed in 4.1.125.Final.
- Fixed in 4.1.125.Final (released Sep 3, 2025, the day of disclosure).
- The latest release, 4.2.20.Final, is not affected.

### [CVE-2021-37137](https://cve.now/CVE-2021-37137): The Snappy frame decoder function doesn't restrict the chunk length which may lead to excessive memory usage.

- Severity: Unrated
- Published: Oct 19, 2021
- Affected: from 4.0.0, fixed in 4.1.68.Final.
- Fixed in 4.1.68.Final (released Sep 9, 2021, 40 days before disclosure).
- The latest release, 4.2.20.Final, is not affected.

### [CVE-2021-37136](https://cve.now/CVE-2021-37136): The Bzip2 decompression decoder function doesn't allow setting size restrictions on the decompressed output data (which affects the allocati

- Severity: Unrated
- Published: Oct 19, 2021
- Affected: fixed in 4.1.68.Final.
- Fixed in 4.1.68.Final (released Sep 9, 2021, 40 days before disclosure).
- The latest release, 4.2.20.Final, is not affected.

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