What is CVE-2025-66489?

CVE-2025-66489 is a critical-severity vulnerability in Cal Cal.com, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 9.8/10. Published 2025-12-03.

How severe is CVE-2025-66489?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Cal Cal.com

CVE-2025-66489

Cal.com is open-source scheduling software. Prior to 5.9.8, A flaw in the login credentials provider allows an attacker to bypass password verification when a TOTP code is provided, potentially gaining unauthorized access to user accounts…

EPSS: 0.008 (51.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Cal Cal.com
Calcom Cal.com — versions < 5.9.8

Weakness classification (CWE)

CWE-303 — Incorrect Implementation of Authentication Algorithm

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2025-66489?: CVE-2025-66489 is a critical-severity vulnerability in Cal Cal.com, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 9.8/10. Published 2025-12-03.
How severe is CVE-2025-66489?: Critical severity. CVSS v3 base score is 9.8 out of 10.