CVE-2026-54130: M365 Copilot Information Disclosure Vulnerability

criticalCVSS 9.8CVE-2026-54130

Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.

CSIRTS triage

vendor: Microsoft product: M365 Copilot Information disclosure

What: Missing authentication for a critical function allows unauthorized information disclosure.
Who is affected: Users of M365 Copilot may be affected.
Urgency: Remediation is critical urgency due to the critical severity rating.
Action: Apply the relevant patches immediately.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch M365 Copilot

Get an email when a new M365 Copilot advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: critical — CVSS 9.8
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54130

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-541300.58% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 44% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-54130	coverage & exploitation status	NVD · CVE.org

Recent advisories for M365 Copilot Information

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-42824: M365 Copilot Information Disclosure Vulnerabilitymsrc · 2026-06-09