CodeIgniter before 2.2.0 makes it easier for attackers to decode session cookies by leveraging fallback to a custom XOR-based encryption scheme when the Mcrypt extension for PHP is not available.
https://www.dionach.com/blog/codeigniter-session-decoding-vulnerability
http://packetstormsecurity.com/files/130609/Seagate-Business-NAS-Unauthenticated-Remote-Command-Execution.html
https://codeigniter.com/userguide2/changelog.html
Source: Mitre, NVD
Published: 2017-09-19
Updated: 2026-05-13
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N
Severity: Medium
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
EPSS: 0.37222