CVE-2026-25818 — CRITICAL (9.1)

Vulnerability Description

HMS Networks Ewon Flexy with firmware before 15.0s4, Cosy+ with firmware 22.xx before 22.1s6, and Cosy+ with firmware 23.xx before 23.0s3 have weak entropy for authentication cookies, allowing an attacker with a stolen session cookie to find the user password by brute-forcing an encryption parameter.

CVSS Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-315

References

FAQ

What is CVE-2026-25818?

CVE-2026-25818 is a vulnerability with a CVSS score of 9.1 (CRITICAL). HMS Networks Ewon Flexy with firmware before 15.0s4, Cosy+ with firmware 22.xx before 22.1s6, and Cosy+ with firmware 23.xx before 23.0s3 have weak entropy for authentication cookies, allowing an atta...

How severe is CVE-2026-25818?

CVE-2026-25818 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-25818?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.