What is CVE-2026-77903?

CVE-2026-77903 is a critical-severity vulnerability in Microsoft Dataverse, classified under Authentication Bypass by Spoofing. CVSS score: 9.0/10. Published 2026-09-17.

How severe is CVE-2026-77903?

Critical severity. CVSS v3 base score is 9.0 out of 10.

Vulnerability in Microsoft Dataverse

CVE-2026-77903

Authentication bypass by spoofing in Microsoft Dataverse allows an unauthorized attacker to elevate privileges over a network.

Published 2026-09-17 · last modified 2026-09-25.

CVSS v3 metric

CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (31.2th percentile), scored 2026-11-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 31.2% 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: 0.004 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

Microsoft Dataverse Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-77903?: CVE-2026-77903 is a critical-severity vulnerability in Microsoft Dataverse, classified under Authentication Bypass by Spoofing. CVSS score: 9.0/10. Published 2026-09-17.
How severe is CVE-2026-77903?: Critical severity. CVSS v3 base score is 9.0 out of 10.