# Netty affected by MadeYouReset HTTP/2 DDoS vulnerability

Advisory record · `GHSA-prj3-ccx8-p6x4`

- **Identifiers:** `GHSA-prj3-ccx8-p6x4` · `CVE-2025-55163`
- **State:** Confirmed
- **Severity:** CVSS 8.2 High
- **Critical:** No
- **Weakness (CWE):** [CWE-770](https://cwe.mitre.org/data/definitions/770.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 13 Aug 2025
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 13 Aug 2025, 19:06 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `io.netty:netty-codec-http2` (Maven): affected `>=4.2.0.Alpha1, <4.2.4.Final || <4.1.124.Final`; fixed in `4.2.4.Final`, `4.1.124.Final`
- `io.grpc:grpc-netty-shaded` (Maven): affected `<1.75.0`; fixed in `1.75.0`

## Machine-written summary

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

> Netty's netty-codec-http2 is affected in versions from 4.2.0.Alpha1 before 4.2.4.Final and in versions before 4.1.124.Final; upgrade to 4.2.4.Final or 4.1.124.Final. grpc-netty-shaded versions before 1.75.0 are also affected; upgrade to 1.75.0. A remote client can send malformed HTTP/2 control frames that cause the server to reset streams while still processing them, which lets the attacker exhaust CPU or memory and cause denial of service. The source gives few details on specific workarounds beyond protocol-level limits on server-sent reset frames.

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

- 8.2 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:P/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:** 0.011, the 66th percentile, on 13 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-prj3-ccx8-p6x4)

## Sources

- [GitHub Advisory Database: GHSA-prj3-ccx8-p6x4](https://github.com/advisories/GHSA-prj3-ccx8-p6x4)
- [OSV: GHSA-prj3-ccx8-p6x4](https://osv.dev/vulnerability/GHSA-prj3-ccx8-p6x4)
- <https://github.com/netty/netty/security/advisories/GHSA-prj3-ccx8-p6x4>
- <https://nvd.nist.gov/vuln/detail/CVE-2025-55163>
- <https://github.com/grpc/grpc-java/commit/6462ef9a11980e168c21d90bbc7245c728fd1a7a>
- <https://github.com/netty/netty/commit/be53dc3c9acd9af2e20d0c3c07cd77115a594cf1>
- <https://github.com/netty/netty>
- <https://www.kb.cert.org/vuls/id/767506>
- <http://www.openwall.com/lists/oss-security/2025/08/16/1>

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-prj3-ccx8-p6x4>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-prj3-ccx8-p6x4/>. Everything for agents: <https://agentprime.io/llms.txt>.