# CVE-2026-62380: Netty before 4.2.16.Final SOCKS Proxy Null Byte Injection

> Attackers can inject null bytes or CRLF into SOCKS proxy fields to spoof domains or alter authentication data in Netty applications.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** CLEANSTART-2026-BC54924, CLEANSTART-2026-NB43165, CLEANSTART-2026-PK97624, CLEANSTART-2026-VB05004, CLEANSTART-2026-VD69518, CLEANSTART-2026-YC22300, DEBIAN-CVE-2026-62380, GHSA-cc6x-ffm5-83wf, GHSA-jmpc-xv4r-m7fw, UBUNTU-CVE-2026-62380

## What is CVE-2026-62380?

CVE-2026-62380 is a medium-severity vulnerability in Netty Netty, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Netty (io.netty:netty-codec-socks) versions 4.2.0.Final through 4.2.16.Final and 4.1.x through 4.1.136.Final contain null byte, CRLF, and credential injection vulnerabilities in the SOCKS4 (Socks4ClientEncoder) and SOCKS5 (Socks5ClientEncoder) client encoders, which fail to validate domain address and authentication (username/password) fields. An attacker able to control these fields can inject null bytes or CRLF characters to truncate or alter values, potentially enabling domain spoofing, SOCKS4 userid truncation, authentication data injection, and protocol confusion. Fixed in 4.2.17.Final and 4.1.137.Final.

Weakness: CWE-626 (Null Byte Interaction Error (Poison Null Byte))

## Which versions are affected by CVE-2026-62380?

It affects 1 product.


Products: Netty Netty.

## How do I fix CVE-2026-62380?

Upgrade to a fixed version.

## Is CVE-2026-62380 being exploited?

There is no known exploitation of CVE-2026-62380 in the wild and no public exploit code.

## Other vulnerabilities in Netty Netty

- [CVE-2026-75595](https://insights.sbomify.com/CVE-2026-75595/): Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext (critical 9.1)
- [CVE-2026-75596](https://insights.sbomify.com/CVE-2026-75596/): Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing (high 8.7)
- [CVE-2026-59901](https://insights.sbomify.com/CVE-2026-59901/): Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang (high 8.7)
- [CVE-2026-55851](https://insights.sbomify.com/CVE-2026-55851/): Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion (high 8.7)
- [CVE-2026-56745](https://insights.sbomify.com/CVE-2026-56745/): Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62380 and fix it if it is affected.

What it is: CVE-2026-62380 is a medium-severity vulnerability in Netty Netty, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62380 in the wild and no public exploit code.

Affected product: Netty Netty. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-62380/ (Markdown: https://insights.sbomify.com/CVE-2026-62380/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62380
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62380
- OSV: https://osv.dev/vulnerability/CVE-2026-62380

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62380/
Summaries are generated and may contain mistakes; the official description above is the record.