CVE-2026-3255
HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function
- State
- Published
- Severity
- 6.5 Medium
- Published
- Feb 27, 2026
- Updated
- Mar 3, 2026
- Reserved
- Feb 26, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L | CISA-ADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
HTTP::Session2TOKUHIROM |
|
References
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68
- https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changesrelease-notes
- https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patchpatch
- http://www.openwall.com/lists/oss-security/2026/02/27/12
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