CVE-2026-3255
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
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Description
HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function. The HTTP::Session2 session id generator returns a SHA-1 hash seeded with the built-in rand function, the epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand() function is unsuitable for cryptographic usage. HTTP::Session2 after version 1.02 will attempt to use the /dev/urandom device to generate a session id, but if the device is unavailable (for example, under Windows), then it will revert to the insecure method described above.
Analysis
HTTP::Session2 before version 1.12 for Perl generates predictable session identifiers on Windows systems when /dev/urandom is unavailable, falling back to weak randomization using rand() combined with guessable values like PID and epoch time. An attacker could predict valid session IDs to hijack user sessions, as SHA-1 hashing of these weak inputs provides insufficient cryptographic protection. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.
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