Critical severity · published Dec 3, 2025
CVE-2025-66489
Cal.com Authentication Bypass via bad TOTP + password checks
9.8
CVSS
1%
EPSS
No
On KEV
Description
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. This issue exists due to problematic conditional logic in the authentication flow. This vulnerability is fixed in 5.9.8.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 62% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CA
cal.com · calcom
< 5.9.8 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-66489
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-66489
Exploit
https://github.com/calcom/cal.com/security/advisories/GHSA-9r3w-4j8q-pw98
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