Amazon Linux 2 Security Advisory: ALAS2-2026-3805
Advisory Released Date: 2026-07-20
Advisory Updated Date: 2026-07-20
CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources.
The generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID is drawn from a small range, the epoch time can be guessed or read from the HTTP Date header, and Perl's rand() is unsuitable for security purposes because it is predictable and reversible.
An attacker who predicts a session id can impersonate the corresponding session and bypass authentication. (CVE-2026-56016)
Affected Packages:
perl-CGI-Session
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update perl-CGI-Session or yum update --advisory ALAS2-2026-3805 to update your system.
noarch:
perl-CGI-Session-4.35-16.amzn2.0.1.noarch
src:
perl-CGI-Session-4.35-16.amzn2.0.1.src