# Mechanize sends credential headers to another origin after a meta refresh

Advisory record · `GHSA-c6rp-p8xm-4q9f`

- **Identifiers:** `GHSA-c6rp-p8xm-4q9f` · `CVE-2026-107399`
- **State:** Confirmed
- **Severity:** CVSS 6.8 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-200](https://cwe.mitre.org/data/definitions/200.html) · [CWE-522](https://cwe.mitre.org/data/definitions/522.html)
- **Tags:** [Information disclosure](https://agentprime.io/advisories/tag/info-disclosure.md) · [Hard-coded credentials](https://agentprime.io/advisories/tag/hard-coded-credentials.md)
- **Published:** 8 Oct 2026
- **Updated:** 8 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 8 Oct 2026, 22:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `mechanize` (RubyGems): affected `<2.14.1`; fixed in `2.14.1`

## Machine-written summary

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

> Mechanize versions before 2.14.1 send headers set through request_headers= to another origin when following a meta refresh, leaking bearer tokens and session cookies. An attacker who can place a meta refresh in a page the agent fetches can capture these credentials, but only when follow_meta_refresh is enabled, which is not the default. Upgrade to mechanize 2.14.1 or later; if you cannot upgrade, keep follow_meta_refresh set to false or avoid putting credentials in request_headers=.

Written 3 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

- 6.8 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0036, the 30th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:21 UTC: First seen by agentprime
- 31 Oct 2026, 14:21 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-c6rp-p8xm-4q9f)

## Sources

- [GitHub Advisory Database: GHSA-c6rp-p8xm-4q9f](https://github.com/advisories/GHSA-c6rp-p8xm-4q9f)
- [OSV: GHSA-c6rp-p8xm-4q9f](https://osv.dev/vulnerability/GHSA-c6rp-p8xm-4q9f)
- <https://github.com/sparklemotion/mechanize/security/advisories/GHSA-c6rp-p8xm-4q9f>
- <https://github.com/sparklemotion/mechanize/pull/676>
- <https://github.com/sparklemotion/mechanize/commit/02a1235842d6eda8d4a5a3d8f13aba2cecf52e4f>
- <https://github.com/sparklemotion/mechanize/commit/84c74df87d15f5d119df268ba6aa79bc1e16a2c3>
- <https://github.com/sparklemotion/mechanize>
- <https://github.com/sparklemotion/mechanize/releases/tag/v2.14.1>

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-c6rp-p8xm-4q9f>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-c6rp-p8xm-4q9f/>. Everything for agents: <https://agentprime.io/llms.txt>.