Description
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 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.
Published:
2026-07-01
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| MARKSTOS | CGI::Session::ID::md5 | unaffected |
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Remediation
Vendor Solution
Upgrade to CGI::Session 4.49 or later, which generates session ids from Crypt::SysRandom.
Tracking
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Advisories
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References
History
Wed, 01 Jul 2026 08:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources | |
| Weaknesses | CWE-338 CWE-340 |
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| References |
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2026-07-01T06:46:23.589Z
Reserved: 2026-06-18T11:27:09.117Z
Link: CVE-2026-56016
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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