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.

The version of perl-CGI-Session installed on the remote host is prior to 4.35-16. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3805 advisory.

    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)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the dfa2ef44-7785-11f1-99fc-40b034429ecf advisory.

    CGI-Session project reports:
    SECURITY: Strengthen cryptographic randomness of MD5 driver.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
328847	Amazon Linux 2 : perl-CGI-Session, --advisory ALAS2-2026-3805 (ALAS-2026-3805)	Nessus	Amazon Linux Local Security Checks	medium
325233	FreeBSD : p5-CGI-Session -- secuity fixes (dfa2ef44-7785-11f1-99fc-40b034429ecf)	Nessus	FreeBSD Local Security Checks	medium
324242	Linux Distros Unpatched Vulnerability : CVE-2026-56016	Nessus	Misc.	medium

Detections

Analytics

CVE-2026-56016

medium

Tenable Plugins

medium

medium

medium