CVE-2026-23478 | Cal.com is open-source scheduling software. From 3.1.6 to be… | CVSS 10.0 CRITICAL

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.

Metadata

CVE ID: CVE-2026-23478
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-01-13 15:47 UTC
Published: 2026-01-13 21:37 UTC
Last updated: 2026-01-14 16:56 UTC
Primary CWE: CWE-602
CWE-602: Client-Side Enforcement of Server-Side Security
Vendor / Product: calcom / cal.com
Sources: cve.org · NVD

Severity & Metrics

10.0 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:L

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: total

Affected products (1)

Vendor	Product	Platform	Versions
calcom	cal.com	—	>= 3.1.6, < 6.0.7

Weakness (CWE)

CWE	Source	Description
CWE-602	cna	CWE-602: Client-Side Enforcement of Server-Side Security
CWE-639	cna	CWE-639: Authorization Bypass Through User-Controlled Key

CVSS scores (1)

Score	Severity	Version	Source	Vector
10.0	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:L

References (1)

https://github.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg https://github.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg