CVE-2026-107399
Mechanize sends credential headers to another origin after a meta refresh
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Mechanize sends credential headers to another origin after a meta refresh
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.
- Record
CVE-2026-107399- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-200, CWE-522
- Updated
- 2026-11-02
EUVDEUVD-2026-95318
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.
- Record
EUVD-2026-95318- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-c6rp-p8xm-4q9f
Mechanize sends credential headers to another origin after a meta refresh
Summary
mechanize applied no trust boundary to a meta refresh, so credentials set through Mechanize#request_headers= followed a refresh that pointed at another origin.
Details
Mechanize::HTTP::Agent#response_follow_meta_refresh fetched the refresh target with no notion of a crossed origin, so @request_headers were re-applied in full. An attacker who could place a meta refresh in a page the agent fetched — through stored content, an open redirect, or control of any page in the crawl — collected the same credentials as through an HTTP redirect, on a code path that had none of the redirect path's protections.
The refresh fetch passes an empty per-request headers hash, so only headers set through Mechanize#request_headers= were exposed.
This requires Mechanize#follow_meta_refresh = true. It is false by default, so an agent in its default configuration is not affected. Crawlers commonly enable it.
Impact
An attacker who can place a meta refresh in any page the agent fetches captures bearer tokens and session cookies set through request_headers=. Disclosure only; no integrity or availability impact.
Patches
Fixed in mechanize v2.14.1. A meta refresh that points at another origin is now subject to the same rule as an HTTP redirect: credentials and cookies are withheld from the request that follows it.
Workarounds
Leave Mechanize#follow_meta_refresh at its default of false, or avoid request_headers= for credentials when it is enabled.
- Record
GHSA-c6rp-p8xm-4q9f- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-200, CWE-522
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-107399- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-200, CWE-522
- Updated
- 2026-11-02
OSV
Mechanize sends credential headers to another origin after a meta refresh
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.
- Record
CVE-2026-107399- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-200, CWE-522
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-107399
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.
- Record
DEBIAN-CVE-2026-107399- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-02
OSVGHSA-c6rp-p8xm-4q9f
Mechanize sends credential headers to another origin after a meta refresh
Summary
mechanize applied no trust boundary to a meta refresh, so credentials set through Mechanize#request_headers= followed a refresh that pointed at another origin.
Details
Mechanize::HTTP::Agent#response_follow_meta_refresh fetched the refresh target with no notion of a crossed origin, so @request_headers were re-applied in full. An attacker who could place a meta refresh in a page the agent fetched — through stored content, an open redirect, or control of any page in the crawl — collected the same credentials as through an HTTP redirect, on a code path that had none of the redirect path's protections.
The refresh fetch passes an empty per-request headers hash, so only headers set through Mechanize#request_headers= were exposed.
This requires Mechanize#follow_meta_refresh = true. It is false by default, so an agent in its default configuration is not affected. Crawlers commonly enable it.
Impact
An attacker who can place a meta refresh in any page the agent fetches captures bearer tokens and session cookies set through request_headers=. Disclosure only; no integrity or availability impact.
Patches
Fixed in mechanize v2.14.1. A meta refresh that points at another origin is now subject to the same rule as an HTTP redirect: credentials and cookies are withheld from the request that follows it.
Workarounds
Leave Mechanize#follow_meta_refresh at its default of false, or avoid request_headers= for credentials when it is enabled.
- Record
GHSA-c6rp-p8xm-4q9f- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Weakness
- CWE-200, CWE-522
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-107399
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.
- Record
UBUNTU-CVE-2026-107399- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mechanizeRubyGems |
before 2.14.1 | 2.14.1 |
ruby-mechanizeDebian:12 |
All versions, plus listed versions 2.10.1-12.10.1-1.12.14.0-12.14.0-22.14.1-12.8.5-1 |
None known |
ruby-mechanizeDebian:13 |
All versions, plus listed versions 2.10.1-12.10.1-1.12.14.0-12.14.0-22.14.1-1 |
None known |
ruby-mechanizeDebian:14 |
before 2.14.1-1, plus listed versions 2.10.1-12.10.1-1.12.14.0-12.14.0-2 |
2.14.1-1 |
mechanizeRubyGems |
before 2.14.1, plus listed versions 0.1.00.1.10.1.20.1.30.2.0 Show 45 moreShow less0.2.10.2.20.2.30.3.00.3.10.4.00.4.10.4.20.4.30.4.40.4.50.4.60.4.70.5.00.5.10.5.20.5.30.5.40.6.00.6.10.6.100.6.110.6.20.6.30.6.40.6.50.6.60.6.70.6.80.6.90.7.00.7.10.7.20.7.30.7.40.7.50.7.60.7.70.7.80.8.00.8.10.8.20.8.30.8.40.8.5 |
2.14.1 |
ruby-mechanizeUbuntu:16.04:LTS |
All versions, plus listed versions 2.7.3-1 |
None known |
ruby-mechanizeUbuntu:18.04:LTS |
All versions, plus listed versions 2.7.5-12.7.5-2 |
None known |
ruby-mechanizeUbuntu:20.04:LTS |
All versions, plus listed versions 2.7.6-1 |
None known |
ruby-mechanizeUbuntu:22.04:LTS |
All versions, plus listed versions 2.7.7-12.7.7-3 |
None known |
ruby-mechanizeUbuntu:24.04:LTS |
All versions, plus listed versions 2.8.5-1 |
None known |
ruby-mechanizeUbuntu:26.10 |
All versions, plus listed versions 2.10.1-1.12.14.0-2 |
None known |
ruby-mechanizeUbuntu:26.04:LTS |
All versions, plus listed versions 2.10.1-1.1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-107399 is a medium vulnerability (CVSS 6.8) in Python-mechanize Mechanize, published October 8, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 30th percentile. Fixed in mechanize 2.14.1.
References
github.com/sparklemotion/mechanize/security/advisories/GHSA-c6rp-p8xm-4q9f
Left out here: 45 versions. The JSON record has them.