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.

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Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 03 Feb 2026 19:30:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:cal:cal.com:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Wed, 14 Jan 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 14 Jan 2026 11:15:00 +0000

Type Values Removed Values Added
First Time appeared Cal
Cal cal.com
Vendors & Products Cal
Cal cal.com

Tue, 13 Jan 2026 22:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Cal.com has an Authentication Bypass via Unvalidated Email in Custom JWT Callback
Weaknesses CWE-602
CWE-639
References
Metrics cvssV4_0

{'score': 10, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-01-14T16:56:25.582Z

Reserved: 2026-01-13T15:47:41.627Z

Link: CVE-2026-23478

cve-icon Vulnrichment

Updated: 2026-01-14T16:56:22.616Z

cve-icon NVD

Status : Analyzed

Published: 2026-01-13T22:16:08.093

Modified: 2026-02-03T19:29:07.787

Link: CVE-2026-23478

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-01-14T11:08:34Z

Weaknesses