Threat Intelligence / CVE / CVE-2026-77903

CVE-2026-77903 — Microsoft Dataverse

CVSS v3.1 9 (CRITICAL) · EPSS 0.3% (higher than 31.9% of all scored CVEs) · Priority 5.8/10 · Published 2026-09-17

As of 2026-09-19, CVE-2026-77903 is a CRITICAL-severity vulnerability in Microsoft Dataverse, CVSS v3.1 9, EPSS 0.3% (31.9th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-77903, most recently “Microsoft September 2026 Cloud Disclosure: 18 Elevation-of-Privilege, Information-Disclosure, and Spoofing Flaws Across Azure and Copilot AI Products, Plus a Windows Secure Kernel EoP (CVE-2026-85921)”.

Last updated: 2026-09-19

What is CVE-2026-77903?

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

The record classifies CVE-2026-77903 under weakness class CWE-290. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 3 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9 — CRITICAL
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
EPSS (FIRST): 0.3% probability of exploitation in the next 30 days, higher than 31.9% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 5.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-09-17, last modified 2026-09-19

Is CVE-2026-77903 being exploited?

It currently carries a trending score of 37 in the Threadlinqs vulnerability feed.

Affected products and versions

Microsoft: Dataverse

How to fix CVE-2026-77903

No vendor patch reference has been recorded for CVE-2026-77903 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-77903

1 tracked threat in the Threadlinqs corpus references CVE-2026-77903, either in the campaign’s CVE list or as an indicator on the campaign record.

Microsoft September 2026 Cloud Disclosure: 18 Elevation-of-Privilege, Information-Disclosure, and Spoofing Flaws Across Azure and Copilot AI Products, Plus a Windows Secure Kernel EoP (CVE-2026-85921) — CRITICAL · 2026-09-18

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-09-19. This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch

msrc.microsoft.com — vendor advisory

Full detection coverage & IOCs for threats exploiting CVE-2026-77903 are available via the Threadlinqs MCP server (Purple tier). View plans →

← all vulnerabilities · Markdown version · Threadlinqs Intelligence