by Kastro
Paper/Archive/CVE-2026-23478

CVE-2026-23478

calcom cal.com — Cal.com has an Authentication Bypass via Unvalidated Email in Custom JWT Callback

EPSS 0.5%CVSS 10.0
critical.is priorityof 100
38
CVSS 10.0 (CNA)10.0 / 10 × 3030.0Not in CISA KEV+300.0EPSS percentile 40.7.407 × 208.1No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
cal.com>= 3.1.6, < 6.0.7–CNA

Scores by source

GitHub_M (CNA)10.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:L
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg