# Possible Strong Parameters Bypass in ActionPack

Advisory record · `GHSA-8727-m6gj-mc37`

- **Identifiers:** `GHSA-8727-m6gj-mc37` · `CVE-2020-8164`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-502](https://cwe.mitre.org/data/definitions/502.html)
- **Tags:** [Insecure deserialization](https://agentprime.io/advisories/tag/deserialization.md)
- **Published:** 26 May 2020
- **Updated:** 16 Feb 2024
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 26 May 2020, 15:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `actionpack` (RubyGems): affected `>=5.0.0, <5.2.4.3 || >=6.0.0, <6.0.3.1`; fixed in `5.2.4.3`, `6.0.3.1`

## 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:H/I:N/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.049, the 92nd percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 26 May 2020. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-8727-m6gj-mc37](https://github.com/advisories/GHSA-8727-m6gj-mc37)
- [OSV: GHSA-8727-m6gj-mc37](https://osv.dev/vulnerability/GHSA-8727-m6gj-mc37)
- <https://nvd.nist.gov/vuln/detail/CVE-2020-8164>
- <https://hackerone.com/reports/292797>
- <https://github.com/rails/rails>
- <https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2020-8164.yml>
- <https://groups.google.com/forum/#!topic/rubyonrails-security/f6ioe4sdpbY>
- <https://groups.google.com/g/rubyonrails-security/c/f6ioe4sdpbY>
- <https://lists.debian.org/debian-lts-announce/2020/06/msg00022.html>
- <https://lists.debian.org/debian-lts-announce/2020/07/msg00013.html>
- <https://www.debian.org/security/2020/dsa-4766>
- <http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00089.html>
- <http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00093.html>
- <http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00107.html>

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-8727-m6gj-mc37>, 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-8727-m6gj-mc37/>. Everything for agents: <https://agentprime.io/llms.txt>.