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CVE-2026-3255

HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function

6.5 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
Low

Exploit likelihood

0.46%Up 0.5 points since Feb 28, 2026
90%50%10%1%

What each source reports

NVD Score used 6.5

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.

Record
CVE-2026-3255
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Weakness
CWE-338, CWE-340
Updated
2026-11-02
CVE List 6.5

HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function

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.

Record
CVE-2026-3255
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Weakness
CWE-340, CWE-338
Updated
2026-11-02
EUVDEUVD-2026-9063 6.5

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.

Record
EUVD-2026-9063
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Updated
2026-11-02
GitHub AdvisoriesGHSA-2p7f-7xjf-8q9q 6.5

HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the...

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.

Record
GHSA-2p7f-7xjf-8q9q
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Weakness
CWE-338
Updated
2026-11-02
OSV 6.5

HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function

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.

Record
CVE-2026-3255
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Weakness
CWE-338, CWE-340
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-3255 is a medium vulnerability (CVSS 6.5) in Tokuhirom Http::session2, published February 27, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.46%, the 40th percentile. No source names a fixed version.

References

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