CVE-2026-64857
tirreno, a security framework, has a session fixation issue in versions prior to 0.10.0.
Overview
CVE-2026-64857 is a known-severity vulnerability. It was published on September 9, 2026.
Technical description
tirreno, a security framework, has a session fixation issue in versions prior to 0.10.0. During authentication, tirreno validates the user's credentials and establishes the authenticated session, but it does not call `session_regenerate_id()` afterward. As a result, the session identifier is not rotated on login, it stays the same before and after authentication. An attacker able to fix a known session identifier in a victim's browser (for example through a network man-in-the-middle position, or a separate cross-site scripting or subdomain cookie-injection issue) could then gain access to the victim's authenticated session. The issue is fixed in v0.10.0. The session identifier is now regenerated on successful authentication, and the previous session is destroyed. There is no configuration-level workaround.
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.
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Frequently asked questions
What is CVE-2026-64857?
CVE-2026-64857 is a known-severity vulnerability. It was published on September 9, 2026.
How severe is CVE-2026-64857?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-64857?
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-2026-64857?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-64857 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.