Mechanize sends credential headers to another host after an HTTP redirect

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.8 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS

• CVE-2026-107715: 0.50% estimated exploitation activity in the next 30 days; percentile 42.97 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary mechanize leaked credentials to the redirect target when an HTTP redirect crossed to another host. Credentials set through Mechanize#requestheaders= leaked even when they were Authorization. Details Two defects, both in lib/mechanize/http/agent.rb. 1. Mechanize#requestheaders= bypassed the redirect strip entirely. #requestaddheaders copied @requestheaders onto every request unconditionally, with no host check, including the request issued after a redirect. The strip in #responseredirect mutated only the per-request headers hash and never touched agent state. Because requestheaders= is the documented way to set a default credential for every request, the header the code explicitly protected — Authorization — was the one most likely to leak. 2. The strip list omitted Proxy-Authorization and Cookie2. Only CREDENTIALHEADERS = ['Authorization'] and COOKIEHEADERS = ['Cookie'] were removed from the per-request headers hash on a cross-host redirect. Cookies held in…

Published by the source

8 Oct 2026, 22:09 UTC

Last modified by the source

8 Oct 2026, 22:15 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-2mwr-xjcg-37j7

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-2mwr-xjcg-37j7

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# Patch Next advisory brief: CVE-2026-107715

Advisory: Mechanize sends credential headers to another host after an HTTP redirect
IDs: CVE-2026-107715, GHSA-2mwr-xjcg-37j7
Record: https://patchnext.com/advisories/cve-2026-107715 (revision 2, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mechanize 2.14.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems mechanize: affected < 2.14.1; fixed in 2.14.1

## Suggested inspection (read-only)
- RubyGems mechanize: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mechanize.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-2mwr-xjcg-37j7 (OSV record GHSA-2mwr-xjcg-37j7 lists affected ranges: RubyGems mechanize >=0 <2.14.1 (fixed))
- Verified: https://github.com/advisories/GHSA-2mwr-xjcg-37j7 (GitHub-reviewed advisory GHSA-2mwr-xjcg-37j7 lists affected ranges: RubyGems mechanize >=0 <2.14.1)

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