CVE-2026-56016

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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/changes
https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/source/lib/CGI/Session/ID/md5.pm
http://www.openwall.com/lists/oss-security/2026/07/01/6

Configurations

No configuration.

History

01 Jul 2026, 18:16

Type	Values Removed	Values Added
References		() http://www.openwall.com/lists/oss-security/2026/07/01/6 -

01 Jul 2026, 15:17

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 5.9

01 Jul 2026, 08:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-01 08:16

Updated : 2026-07-02 17:39

NVD link : CVE-2026-56016

Mitre link : CVE-2026-56016

CVE.ORG link : CVE-2026-56016

JSON object : View

Products Affected

No product.

CWE

CWE-338

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

CWE-340

Generation of Predictable Numbers or Identifiers

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