CVE-2025-66489
CVE-2025-66489 is a critical-severity vulnerability in Cal Cal.com with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-303.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 9.9
- EPSS exploit prediction: 1% (52nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-201128
- Weakness: CWE-303
- Affected product: Cal Cal.com
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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. This issue exists due to problematic conditional logic in the authentication flow. This vulnerability is fixed in 5.9.8.
- How severe is CVE-2025-66489?
- CVE-2025-66489 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2025-66489 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-66489?
- CVE-2025-66489 affects Cal Cal.com. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2025-66489?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2025-66489 have an EU (EUVD) identifier?
- Yes. CVE-2025-66489 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201128.
- When was CVE-2025-66489 published?
- CVE-2025-66489 was published on 2025-12-03 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:cal:cal.com:*:*:*:*:*:*:*:*
More vulnerabilities in Cal Cal.com
- CVE-2026-23478 — Critical (CVSS 9.8): Cal.com is open-source scheduling software. From 3.1.6 to before 6.0.7, there is a vulnerability in a custom NextAuth…
- CVE-2023-1647 — High (CVSS 8.8): Improper Access Control in GitHub repository calcom/cal.com prior to 2.7.
- CVE-2023-37919 — Medium (CVSS 6.5): Cal.com is open-source scheduling software. A vulnerability allows active sessions associated with an account to remain…
All CVEs affecting Cal Cal.com →
Other CWE-303 vulnerabilities
- CVE-2025-13390 — Critical (CVSS 10.0): The WP Directory Kit plugin for WordPress is vulnerable to authentication bypass in all versions up to, and including,…
- CVE-2025-12421 — Critical (CVSS 9.9): Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that…
- CVE-2025-12419 — Critical (CVSS 9.9): Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly…
- CVE-2025-21311 — Critical (CVSS 9.8): Windows NTLM V1 Elevation of Privilege Vulnerability
- CVE-2024-10127 — Critical (CVSS 9.8): Authentication bypass condition in LDAP authentication in M-Files server versions before 24.11 supported usage of…
- CVE-2024-4985 — Critical (CVSS 9.8): An authentication bypass vulnerability was present in the GitHub Enterprise Server (GHES) when utilizing SAML single…