CVE-2025-40923 Affecting libplack-middleware-session-perl package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published17 Jul 2025
- disclosed16 Jul 2025
Introduced: 16 Jul 2025
NewCVE-2025-40923 (opens in a new tab)How to fix?
There is no fixed version for Debian:11 libplack-middleware-session-perl.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libplack-middleware-session-perl package and not the libplack-middleware-session-perl package as distributed by Debian.
See How to fix? for Debian:11 relevant fixed versions and status.
Plack-Middleware-Session before version 0.35 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.
Predicable session ids could allow an attacker to gain access to systems.
References
- https://security-tracker.debian.org/tracker/CVE-2025-40923
- https://github.com/plack/Plack-Middleware-Session/commit/1fbfbb355e34e7f4b3906f66cf958cedadd2b9be.patch
- https://github.com/plack/Plack-Middleware-Session/pull/52
- https://metacpan.org/release/MIYAGAWA/Plack-Middleware-Session-0.34/source/lib/Plack/Session/State.pm#L22
- https://security.metacpan.org/docs/guides/random-data-for-security.html