Auth bypass in Cal Cal.com
CVE-2026-23478
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (37.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000
Affected products
- Cal Cal.com
- Calcom Cal.com — versions >= 3.1.6, < 6.0.7
Weakness classification (CWE)
References
- github.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-23478?
- CVE-2026-23478 is a critical-severity vulnerability in Cal Cal.com, classified under CWE-602. CVSS score: 9.8/10. Published 2026-01-13.
- How severe is CVE-2026-23478?
- Critical severity. CVSS v3 base score is 9.8 out of 10.