CVE & CISA-KEV Catalog

CVE-2026-64857

MEDIUM
5.3
CVSS v4
NVD

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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v4 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone

Impact

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploit Intelligence

0.27%probability of exploitation in 30 days
19thpercentile

Low risk: more likely to be exploited than 19% of all known CVEs.

References

Other references2

Related Vulnerabilities

Other CWE-384 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2018-11714Critical9.868%--
CVE-2018-18925Critical9.831%--
CVE-2019-12258High7.523%-Fix
CVE-2018-17199High7.520%-Fix
CVE-2019-10008High8.819%--
CVE-2024-50339Medium5.319%-Fix

Common questions

How do I fix CVE-2026-64857?

No published fix for CVE-2026-64857 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-64857 being actively exploited?

Not that we know of. CVE-2026-64857 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.

How severe is CVE-2026-64857?

CVE-2026-64857 has a CVSS v4 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-09.