# Puma PROXY Protocol v1 Accepts Repeated Protocol Headers on Persistent Connections

Advisory record · `GHSA-2vqw-3mp8-cgmx`

- **Identifiers:** `GHSA-2vqw-3mp8-cgmx` · `CVE-2026-47737`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-290](https://cwe.mitre.org/data/definitions/290.html) · [CWE-345](https://cwe.mitre.org/data/definitions/345.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md) · [CWE-345](https://agentprime.io/advisories/tag/cwe-345.md)
- **Published:** 9 Jun 2026
- **Updated:** 2 Nov 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 9 Jun 2026, 00:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `puma` (RubyGems): affected `>=8.0.0, <8.0.2 || >=5.5.0, <7.2.1`; fixed in `8.0.2`, `7.2.1`

## 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

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0018, the 7th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 9 Jun 2026, 00:09 UTC: [Confirmed by GitHub Advisory Database](https://github.com/advisories/GHSA-2vqw-3mp8-cgmx)
- 31 Oct 2026, 15:16 UTC: First seen by agentprime
- 31 Oct 2026, 15:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-2vqw-3mp8-cgmx)

## Sources

- [GitHub Advisory Database: GHSA-2vqw-3mp8-cgmx](https://github.com/advisories/GHSA-2vqw-3mp8-cgmx)
- [OSV: GHSA-2vqw-3mp8-cgmx](https://osv.dev/vulnerability/GHSA-2vqw-3mp8-cgmx)
- <https://github.com/puma/puma/security/advisories/GHSA-2vqw-3mp8-cgmx>
- <https://github.com/puma/puma/pull/3944>
- <https://github.com/puma/puma/pull/3947>
- <https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f>
- <https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58>
- <https://github.com/puma/puma>
- <https://github.com/puma/puma/releases/tag/v7.2.1>
- <https://github.com/puma/puma/releases/tag/v8.0.2>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2026-47737.yml>
- <https://nvd.nist.gov/vuln/detail/cve-2026-47737>
- <https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-47737>

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-2vqw-3mp8-cgmx>, 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-2vqw-3mp8-cgmx/>. Everything for agents: <https://agentprime.io/llms.txt>.