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CVE-2025-40923

21
FAUCET Score

CVE-2025-40923 describes an insecure session ID generation vulnerability in Plack-Middleware-Session for Perl, specifically versions prior to 0.35. The default session ID generator uses predictable inputs like the PID, epoch time, and the cryptographically weak built-in rand function, making session IDs guessable. This flaw carries a CVSS score of 7.3 (HIGH) due to its network-based attack vector, low complexity, and potential for low impact on confidentiality, integrity, and availability. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
MIYAGAWAPlack::Middleware::Session
>= 0.01, < 0.35CNA affecteddefault unaffected

CVSS Data

CVSS version used by this source: 3.1

7.3HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
Exploitability Score
3.9
Impact Score
3.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.33%
Probability of exploitation in next 30 days
EPSS Percentile
25.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0033 is in the 7th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

github.com / plack/Plack-Middleware-Session/commit/1fbfbb355e34e7f4b3906f66cf958cedadd2b9be.patch
github.com / plack/Plack-Middleware-Session/pull/52
metacpan.org / release/MIYAGAWA/Plack-Middleware-Session-0.34/source/lib/Plack/Session/State.pm
security.metacpan.org / docs/guides/random-data-for-security.html
openwall.com / lists/oss-security/2025/07/16/4