CVE-2026-23478NVD

Vulnerability Summary

Cal.com is open-source scheduling software. From 3.1.6 to before 6.0.7, there is a vulnerability in a custom NextAuth JWT callback that allows attackers to gain full authenticated access to any user's account by supplying a target email address via session.update(). This vulnerability is fixed in 6.0.7.

Severity Level

CRITICAL(10.0)

Published Date

Jan 13, 2026

Last Modified

Feb 3, 2026

Exploitation Status

No confirmed exploitation yet

EPSS Score (30-Day)

Data Pending

Root Weakness (CWE)

CWE-602: Unknown/Unlisted Weakness ↗

Refer to the official MITRE database for detailed architectural specifications regarding this weakness.

CWE-639: Unknown/Unlisted Weakness ↗

Refer to the official MITRE database for detailed architectural specifications regarding this weakness.

CVSS v4.0 Base Metrics — Score 10.0 (CRITICAL)

Attack VectorNetwork

Attack ComplexityLow

Attack RequirementsNone

Privileges RequiredNone

User InteractionNone

Confidentiality (Vulnerable System)High

Integrity (Vulnerable System)High

Availability (Vulnerable System)High

Confidentiality (Subsequent System)High

Integrity (Subsequent System)High

Availability (Subsequent System)Low

CVSS v3.1 Base Metrics — Score 9.8 (CRITICAL)

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

Affected & Patched Versions

Affected Versions

Cal Cal.com >= 3.1.6 and < 6.0.7

Patched Versions

Cal Cal.com 6.0.7

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