CVE-2025-40926
Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.43% probability · 37th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-338, CWE-340
- Affected
- kazeburo/plack\
- Source
- 9b29abf9-4ab0-4765-b253-1875cd9b441e
References
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/commit/760bb358b8f53e52cf415888a4ac858fd99bb24e.patchPatch
- https://github.com/kazeburo/Plack-Middleware-Session-Simple/pull/4Issue Tracking, Patch
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.04/source/lib/Plack/Middleware/Session/Simple.pm#L43Issue Tracking, Product
- https://metacpan.org/release/KAZEBURO/Plack-Middleware-Session-Simple-0.05/changes
- https://security.metacpan.org/docs/guides/random-data-for-security.htmlThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2025-40923Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.