CVE-2026-8503: Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids. Apache::Session::Generate::SHA256 generated session id...

Description

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids. Apache::Session::Generate::SHA256 generated session ids insecurely. The default session id generator returns a SHA-256 hash of the built-in rand() function, the epoch time, and the PID, that is hashed again. These are predictable, low-entropy sources. Predicable session ids could allow an attacker to gain access to systems. Note that version 1.3.19 has a fallback without warning to use insecure session generation method if the call to Crypt::URandom::urandom fails. However, this is unlikely as Crypt::URandom is a hardcoded requirement of the module. This issue is similar to CVE-2025-40931 for Apache::Session::Generate::MD5.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.24%

15.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Guimard	Apache\	< 1.3.19	Session\

References

Timeline

Published: May 15, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-8503?

Apache::Session::Generate::SHA256 versions before 1.3.19 for Perl create insecure session ids. Apache::Session::Generate::SHA256 generated session ids insecurely. The default session id generator returns a SHA-256 hash of the built-in rand() function, the epoch time, and the PID, that is hashed again. These are predictable, low-entropy sources. Predicable session ids could allow an attacker to gain access to systems. Note that version 1.3.19 has a fallback without warning to use insecure session generation method if the call to Crypt::URandom::urandom fails. However, this is unlikely as Crypt::URandom is a hardcoded requirement of the module. This issue is similar to CVE-2025-40931 for Apache::Session::Generate::MD5.

How severe is CVE-2026-8503?

CVE-2026-8503 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.

How do I fix CVE-2026-8503?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.