CVE-2025-66489

Q: How do I fix CVE-2025-66489?

Upgrade cal.com to 5.9.8 or later.

Q: Is CVE-2025-66489 being actively exploited?

Not that we know of. CVE-2025-66489 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.85% is the estimated probability that it will be exploited in the next 30 days. That is higher than 55% of all scored CVEs.

Q: How severe is CVE-2025-66489?

CVE-2025-66489 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2025-66489 affect?

Published advisories record a fix for cal.com (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

CRITICAL

9.8

CVSS v3

NVD

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.

CWE-303

How to fix

Remediation Available

cal.comNVD

Affected:< 5.9.8Fixed in:5.9.8CVE-2025-66489derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.85%probability of exploitation in 30 days

55thpercentile

Moderate risk: more likely to be exploited than 55% of all known CVEs.

References

Exploit1

github.com

Related Vulnerabilities

Other CWE-303 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-7593	Critical	9.8	100%	KEV	-
CVE-2023-29357	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-8863	High	8.8	77%	-	-
CVE-2023-32152	Medium	6.5	29%	-	-
CVE-2023-32148	Medium	6.5	29%	-	-
CVE-2022-20695	Critical	10.0	20%	-	-

Common questions

How do I fix CVE-2025-66489?

Upgrade cal.com to 5.9.8 or later.

Is CVE-2025-66489 being actively exploited?

Not that we know of. CVE-2025-66489 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.85% is the estimated probability that it will be exploited in the next 30 days. That is higher than 55% of all scored CVEs.

How severe is CVE-2025-66489?

CVE-2025-66489 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2025-66489 affect?

Published advisories record a fix for cal.com (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-13.