{"cve":"CVE-2026-64857","nvd":{"published":"2026-09-09T14:17:13.073","modified":"2026-09-09T20:20:21.673","status":"Deferred","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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","score":5.3},"cvss_v3":null,"cwes":["CWE-384"],"references":["https://github.com/tirrenotechnologies/tirreno/releases/tag/v0.10.0","https://github.com/tirrenotechnologies/tirreno/security/advisories/GHSA-gwcm-4p9m-9mvr"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:53.108888569+00:00"},"epss":{"cve":"CVE-2026-64857","score":0.0047,"percentile":0.40661,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}