What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-08 · updated 2026-10-14
• Weakness: CWE-200

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.

Affected products

• sparklemotion mechanize: before 2.15.0

References

• https://github.com/sparklemotion/mechanize/commit/02a1235842d6eda8d4a5a3d8f13aba2cecf52e4f
• https://github.com/sparklemotion/mechanize/commit/84c74df87d15f5d119df268ba6aa79bc1e16a2c3
• https://github.com/sparklemotion/mechanize/pull/676
• https://github.com/sparklemotion/mechanize/releases/tag/v2.14.1
• https://github.com/sparklemotion/mechanize/security/advisories/GHSA-c6rp-p8xm-4q9f

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