CVE-2025-40926CRITICAL 9.8EPSS p34.5%
CVE-2025-40926CVE-2025-40926
Description
Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely.
The default 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.
Predictable session ids could allow an attacker to gain access to systems.
Plack::Middleware::Session::Simple is intended to be compatible with Plack::Middleware::Session, which had a similar security issue CVE-2025-40923.
Scoring
| CVSS 3.1 | 9.8 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 0.43% probability of exploitation · percentile 34.5% · 2026-06-19T12:03:05Z |
| Published | 2026-03-05 |
| Last modified | 2026-03-12 |
Underlying weaknesses· 2
References
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patch
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changes
- https://security.metacpan.org/docs/guides/random-data-for-security.html
- https://www.cve.org/CVERecord?id=CVE-2025-40923
2
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)cwe-338 | 0% | live |
| Weakness | Generation of Predictable Numbers or Identifierscwe-340 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.