# CVE-2026-3256

## Summary

- **CVE ID:** CVE-2026-3256
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-340, CWE-338
- **Published:** Mar 28, 2026
- **Last Modified:** Sep 17, 2026

## Description

HTTP::Session versions through 0.53 for Perl defaults to using insecurely generated session ids.

HTTP::Session defaults to using HTTP::Session::ID::SHA1 to generate session ids using a SHA-1 hash seeded with the built-in rand function, the high resolution 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.

The distribution includes HTTP::session::ID::MD5 which contains a similar flaw, but uses the MD5 hash instead.

## Affected Products

- KTAT — HTTP::Session (0)

## References

- [CNA](https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/SHA1.pm)
- [CNA](https://metacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/MD5.pm)
- [CNA](https://security.metacpan.org/docs/guides/random-data-for-security.html)
- [CVE](http://www.openwall.com/lists/oss-security/2026/03/28/5)
- [CNA](https://metacpan.org/release/TOKUHIROM/http-session-0.54/changes)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.53%
- **EPSS Percentile:** 43.6

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._