CVE-2026-107715: Mechanize sends credential headers to another host after an HTTP redirect

Description

The Mechanize library is used for automating interaction with websites. Prior to 2.14.1, Mechanize sends caller-supplied credential headers to a different host after an HTTP redirect. Mechanize#request_headers= is reapplied by Mechanize::HTTP::Agent#request_add_headers even after Mechanize::HTTP::Agent#response_redirect strips per-request headers, and the protected header lists omit Proxy-Authorization and Cookie2. An attacker who controls a redirect target can capture bearer tokens or session cookies supplied through request_headers= or the per-request headers argument, while Mechanize#cookie_jar and Mechanize::HTTP::AuthStore are not affected. This issue is fixed in version 2.14.1.

CVSS vector

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

Attack vector

Network

Complexity

High

Privileges

None

User interaction

None

Confidentiality

High

Integrity

None

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.5% · higher than 43% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

ME

mechanize · sparklemotion

< 2.15.0 · source: vendor