CVE-2025-40924
CVE-2025-40924 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-338.
Key facts
- Severity: Medium (CVSS 3.x base score 6.5)
- EPSS exploit prediction: 0% (16th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-21775
- Weakness: CWE-338
- Published:
- Last modified:
Description
Catalyst::Plugin::Session before version 0.44 for Perl generates session ids insecurely. The session id is generated from a (usually SHA-1) hash of a simple counter, the epoch time, the built-in rand function, the PID and the current Catalyst context. This information is of low entropy. 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.
Frequently asked questions
- What is CVE-2025-40924?
- Catalyst::Plugin::Session before version 0.44 for Perl generates session ids insecurely. The session id is generated from a (usually SHA-1) hash of a simple counter, the epoch time, the built-in rand function, the PID and the current Catalyst context. This information is of low entropy. 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.
- How severe is CVE-2025-40924?
- CVE-2025-40924 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2025-40924 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2025-40924?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2025-40924 have an EU (EUVD) identifier?
- Yes. CVE-2025-40924 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21775.
- When was CVE-2025-40924 published?
- CVE-2025-40924 was published on 2025-07-17 and last updated on 2026-06-17.
References
- https://github.com/perl-catalyst/Catalyst-Plugin-Session/commit/c0e2b4ab1e42ebce1008286db8c571b6ee98c22c.patch
- https://github.com/perl-catalyst/Catalyst-Plugin-Session/pull/5
- https://metacpan.org/release/HAARG/Catalyst-Plugin-Session-0.43/source/lib/Catalyst/Plugin/Session.pm#L632
Other CWE-338 vulnerabilities
- CVE-2026-56141 — Critical (CVSS 9.8): In JetBrains Hub before 2026.1.13757, 2025.3.148033, 2025.2.148048, 2025.1.148120, 2024.3.148430, 2024.2.148429 account…
- CVE-2026-3256 — Critical (CVSS 9.8): HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids. HTTP::Session defaults…
- CVE-2025-15604 — Critical (CVSS 9.8): Amon2 versions before 6.17 for Perl use an insecure random_string implementation for security functions. In versions…
- CVE-2025-40926 — Critical (CVSS 9.8): Plack::Middleware::Session::Simple versions before 0.05 for Perl generates session ids insecurely. The default session…
- CVE-2026-2439 — Critical (CVSS 9.8): Concierge::Sessions versions from 0.8.1 before 0.8.5 for Perl generate insecure session ids. The generate_session_id…
- CVE-2025-15578 — Critical (CVSS 9.8): Maypole versions from 2.10 through 2.13 for Perl generates session ids insecurely. The session id is seeded with the…