MARKSTOS CGI::Session::ID::md5 up to 4.48 on Perl rand generation of predictable numbers or identifiers

Summaryinfo

A vulnerability was found in MARKSTOS CGI::Session::ID::md5 up to 4.48 on Perl. It has been classified as problematic. Impacted is the function rand. This manipulation causes generation of predictable numbers or identifiers. This vulnerability is tracked as CVE-2026-56016. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in MARKSTOS CGI::Session::ID::md5 up to 4.48 on Perl and classified as problematic. Affected by this vulnerability is the function rand. The manipulation with an unknown input leads to a generation of predictable numbers or identifiers vulnerability. The CWE definition for the vulnerability is CWE-340. The product uses a scheme that generates numbers or identifiers that are more predictable than required. As an impact it is known to affect confidentiality. The summary by CVE is:

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 advisory is shared at metacpan.org. This vulnerability is known as CVE-2026-56016 since 06/18/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1600.001 for this issue.

Upgrading to version 4.49 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-40927). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• MARKSTOS

Name

• CGI::Session::ID::md5

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30
• 4.31
• 4.32
• 4.33
• 4.34
• 4.35
• 4.36
• 4.37
• 4.38
• 4.39
• 4.40
• 4.41
• 4.42
• 4.43
• 4.44
• 4.45
• 4.46
• 4.47
• 4.48

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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