CPANSA-WWW-Mechanize-Cached-2026-8612: WWW-Mechanize-Cached vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-05-15T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-05-15T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 5.3 | Severity | |
| Original language | Language | en | |
| Also referred to | |||
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.
Vulnerabilities
CVE-2026-8612
Vulnerability DescriptionWWW::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.
| Weakness | CWE-502 : Deserialization of Untrusted Data |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| WWW-Mechanize-Cached less than 2.00 |
|
Fixed
- WWW-Mechanize-Cached greater than or equal 2.00
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-WWW-Mechanize-Cached-2026-8612 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-www-mechanize-cached-2026-8612.json - https://github.com/libwww-perl/WWW-Mechanize-Cached/commit/b821647deeedf83490ebc1db91d959d942300ce0.patch external
https://github.com/libwww-perl/WWW-Mechanize-Cached/commit/b821647deeedf83490ebc1db91d959d942300ce0.patch - https://github.com/libwww-perl/WWW-Mechanize-Cached/pull/36 external
https://github.com/libwww-perl/WWW-Mechanize-Cached/pull/36 - https://metacpan.org/release/OALDERS/WWW-Mechanize-Cached-2.00/changes external
https://metacpan.org/release/OALDERS/WWW-Mechanize-Cached-2.00/changes - http://www.openwall.com/lists/oss-security/2026/05/15/1 external
http://www.openwall.com/lists/oss-security/2026/05/15/1 - CVE-2026-8612 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2026-8612
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Fri May 15 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/