CVE-2025-40931 Affecting libapache-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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- published5 Mar 2026
- disclosed5 Mar 2026
Introduced: 5 Mar 2026
CVE-2025-40931 (opens in a new tab)How to fix?
There is no fixed version for Debian:13 libapache-session-perl.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libapache-session-perl package and not the libapache-session-perl package as distributed by Debian.
See How to fix? for Debian:13 relevant fixed versions and status.
Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id.
Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 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.
Note that the libapache-session-perl package in some Debian-based Linux distributions may be patched to use Crypt::URandom.
References
- https://security-tracker.debian.org/tracker/CVE-2025-40931
- https://github.com/chorny/Apache-Session/issues/4
- https://metacpan.org/dist/Apache-Session/source/lib/Apache/Session/Generate/MD5.pm#L27
- https://rt.cpan.org/Ticket/Display.html?id=173631
- https://security.metacpan.org/docs/guides/random-data-for-security.html
- http://www.openwall.com/lists/oss-security/2026/03/05/3
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=930659
- https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/work_items/1633
- https://metacpan.org/pod/Apache::Session::Generate::Random
- https://salsa.debian.org/perl-team/modules/packages/libapache-session-perl/-/commit/bdabd71c2f91b18526e31a9dc52b4c17b3d246b7#898a4b8b00022df1b8689910b67707f3e738d180
- https://www.openwall.com/lists/oss-security/2019/06/15/1