{"id":"CVE-2026-3255","aliases":["EUVD-2026-9063","GHSA-2p7f-7xjf-8q9q"],"status":"published","title":"HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.00461,"percentile":0.40229,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-338","CWE-340"],"published":"2026-02-27T20:12:35Z","modified":"2026-10-28T02:30:44Z","products":[{"vendor":"tokuhirom","product":"http::session2"},{"vendor":"tokuhirom","product":"http\\"}],"references":[{"url":"https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.11/source/lib/HTTP/Session2/Random.pm#L35","tags":["Issue Tracking","web"]},{"url":"https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.01/source/lib/HTTP/Session2/ServerStore.pm#L68","tags":["Issue Tracking","web"]},{"url":"https://metacpan.org/release/TOKUHIROM/HTTP-Session2-1.12/changes","tags":["release-notes","Release Notes","advisory"]},{"url":"https://github.com/tokuhirom/HTTP-Session2/commit/9cfde4d7e0965172aef5dcfa3b03bb48df93e636.patch","tags":["patch","Patch","fix"]},{"url":"http://www.openwall.com/lists/oss-security/2026/02/27/12","tags":["Mailing List","Third Party Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3255","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2p7f-7xjf-8q9q"},{"url":"https://cpan.org/modules","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3255.json","tags":["advisory"]},{"url":"https://github.com/tokuhirom/HTTP-Session2","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-3255","title":"HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","status":"published","published":"2026-02-27T20:12:35.414Z","modified":"2026-03-03T20:23:53.16Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"adp"}],"cwes":["CWE-340","CWE-338"],"updated_at":"2026-11-02T13:49:09.229322Z"}],"euvd":[{"id":"EUVD-2026-9063","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","status":"published","published":"2026-02-27T20:12:35Z","modified":"2026-03-03T20:23:53Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T19:48:11.637968Z"}],"ghsa":[{"id":"GHSA-2p7f-7xjf-8q9q","title":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the...","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","status":"published","published":"2026-02-27T21:31:22Z","modified":"2026-03-03T21:31:11Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T15:06:26.357639Z"}],"nvd":[{"id":"CVE-2026-3255","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","status":"published","published":"2026-02-27T20:21:41.18Z","modified":"2026-06-17T10:43:17.03Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"primary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-338","CWE-340"],"updated_at":"2026-11-02T14:12:07.420927Z"}],"osv":[{"id":"CVE-2026-3255","title":"HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function","description":"HTTP::Session2 versions before 1.12 for Perl for Perl may generate weak session ids using the rand() function.\n\nThe 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.\n\nHTTP::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.","status":"published","published":"2026-02-27T20:12:35.414Z","modified":"2026-10-28T02:30:44.740335219Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","level":"medium"}],"cwes":["CWE-338","CWE-340"],"updated_at":"2026-11-02T15:45:01.548715Z"}]}}