# CVE-2026-23478

## Summary

- **CVE ID:** CVE-2026-23478
- **Severity:** CRITICAL
- **CVSS Score:** 10 (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)
- **CWE:** CWE-602, CWE-639
- **Published:** Jan 13, 2026
- **Last Modified:** Mar 12, 2026

## 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.

## Affected Products

- calcom — cal.com (>= 3.1.6, < 6.0.7)

## References

- [CNA](https://github.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.46%
- **EPSS Percentile:** 38.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._