CVE-2025-66489 | Cal.com is open-source scheduling software. Prior to 5.9.8, … | CVSS 9.9 CRITICAL

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.

Metadata

CVE ID: CVE-2025-66489
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2025-12-02 22:44 UTC
Published: 2025-12-03 19:44 UTC
Last updated: 2025-12-03 21:48 UTC
Primary CWE: CWE-303
CWE-303: Incorrect Implementation of Authentication Algorith…
Vendor / Product: calcom / cal.com
Sources: cve.org · NVD

Severity & Metrics

9.9 CRITICAL CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
calcom	cal.com	—	< 5.9.8

Weakness (CWE)

CWE	Source	Description
CWE-303	cna	CWE-303: Incorrect Implementation of Authentication Algorithm

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.9	CRITICAL	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N

References (1)

https://github.com/calcom/cal.com/security/advisories/GHSA-9r3w-4j8q-pw98 https://github.com/calcom/cal.com/security/advisories/GHSA-9r3w-4j8q-pw98