CVE-2026-8612

Vulnerability Description

WWW::Mechanize::Cached versions before 2.00 for Perl deserialize cached HTTP responses from a world-writable on-disk cache, enabling local response forgery and code execution. With no explicit cache backend, WWW::Mechanize::Cached constructs a default Cache::FileCache under /tmp/FileCache without overriding the backend's documented directory_umask of 000, so the cache root and its subdirectories are created mode 0777 with no sticky bit. Cache entries are named by sha1_hex of the request and read back through Storable::thaw on the next cache hit. A local attacker with write access to the cache tree can replace a victim's cache entry for a known URL with an arbitrary frozen HTTP::Response blob, causing the victim's next get() of that URL to return attacker controlled response bytes. Because the bytes are passed to Storable::thaw, a victim process that has loaded any class with a side-effectful STORABLE_thaw, DESTROY, or overload hook can be escalated to arbitrary code execution.

CVSS Score

Affected Products

Related Weaknesses (CWE)

References

• https://github.com/libwww-perl/WWW-Mechanize-Cached/commit/b821647deeedf83490ebcPatch
• https://github.com/libwww-perl/WWW-Mechanize-Cached/pull/36Issue TrackingPatch
• https://metacpan.org/release/OALDERS/WWW-Mechanize-Cached-2.00/changesRelease Notes
• http://www.openwall.com/lists/oss-security/2026/05/15/1Mailing ListThird Party Advisory