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CVE-2026-3256

9.8 · CRITICAL

HTTP::Session versions before 0.54 for Perl defaults to using insecurely generated session ids.

Published Mar 28, 2026CWE-338EPSS 0.71%

Overview

CVE-2026-3256 is a critical-severity vulnerability. It was published on March 28, 2026 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

HTTP::Session versions before 0.54 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refmetacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/MD5.pmRefmetacpan.org/release/KTAT/http-session-0.53/source/lib/HTTP/Session/ID/SHA1.pmRefmetacpan.org/release/TOKUHIROM/http-session-0.54/changesRefsecurity.metacpan.org/docs/guides/random-data-for-security.htmlRefwww.openwall.com/lists/oss-security/2026/03/28/5

How CyberStrike helps

Frequently asked questions

What is CVE-2026-3256?

CVE-2026-3256 is a critical-severity vulnerability. It was published on March 28, 2026 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-3256?

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-3256?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-3256?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-3256 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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