Critical (9.8) in squirrelmail squirrelmail. EPSS 1.4% chance of exploitation in the next 30 days.
compose.php in SquirrelMail 1.4.22 calls unserialize for the $mailtodata value, which originates from an HTTP GET request. This is related to mailto.php.
Severity
CVSS 3.1
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
1.4% chance of exploitation in the next 30 days; higher than 73% of CVEs (scores of 2026-10-31)