CVE-2026-3255CWE-338CWE-340

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

Medium · published February 27, 2026

CVSS v3.1
6.5
EPSS
1%
Percentile
42.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00501 · 42.0th percentile
Weaknesses
CWE-338 · Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG); CWE-340 · Generation of Predictable Numbers or Identifiers
Published
2026-02-27T20:12Z
EPSS history
Timeline
  • 27 FEB 20:12Z
    HTTP::Session2 versions before 1.12 for Perl may generate weak session ids using the rand() function
    cvelistv5