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Vulnerability record · CVE-2025-40931 · published 5 March 2026

CVE-2025-40931: Chorny apache\ vulnerability

CChorny · Apache\

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.

9.1 CVSS 3.1 Critical EPSS 0.58% · top 54.3% CWE-338 · CWE-338CWE-340 · CWE-340
9.1CVSS 3.1 base score
0.58%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=930659
https://github.com/chorny/Apache-Session/issues/4 Issue Tracking
https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/work_items/1633
https://metacpan.org/dist/Apache-Session/source/lib/Apache/Session/Generate/MD5.pm#L27 Product
https://metacpan.org/pod/Apache::Session::Generate::Random
https://rt.cpan.org/Ticket/Display.html?id=173631 Third Party Advisory
https://salsa.debian.org/perl-team/modules/packages/libapache-session-perl/-/commit/bdabd71c2f91b18526e31a9dc52b4c17b3d2
https://security.metacpan.org/docs/guides/random-data-for-security.html Mailing ListThird Party Advisory
https://www.openwall.com/lists/oss-security/2019/06/15/1
http://www.openwall.com/lists/oss-security/2026/03/05/3 Mailing ListThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.1CVE-2013-10075Chorny apache\ vulnerabilityApache::Session versions through 1.94 for Perl re-creates deleted sessions. The session stores Apache::Session::Store::File and Apache::Session::Stor…EPSS 0.36%9.1CVE-2026-5081Chorny apache\ vulnerabilityApache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are insecure. Apache::Session::Generate::ModUniqueId (add…EPSS 0.49%

Source: NIST National Vulnerability Database (record CVE-2025-40931), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.