How severe is CVE-2026-54130?

CVE-2026-54130 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-54130 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54130?

CVE-2026-54130 affects Microsoft 365 Copilot. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-54130?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-54130 have an EU (EUVD) identifier?

Yes. CVE-2026-54130 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37946.

When was CVE-2026-54130 published?

CVE-2026-54130 was published on 2026-06-18 and last updated on 2026-06-25.

CVE-2026-54130

CVE-2026-54130 is a critical-severity vulnerability in Microsoft 365 Copilot with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-37946
Weakness: CWE-306
Affected product: Microsoft 365 Copilot
Published: 2026-06-18
Last modified: 2026-06-25

Description

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

Frequently asked questions

What is CVE-2026-54130?: Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.
How severe is CVE-2026-54130?: CVE-2026-54130 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-54130 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54130?: CVE-2026-54130 affects Microsoft 365 Copilot. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-54130?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-54130 have an EU (EUVD) identifier?: Yes. CVE-2026-54130 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37946.
When was CVE-2026-54130 published?: CVE-2026-54130 was published on 2026-06-18 and last updated on 2026-06-25.

References

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

Affected products (1)

cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:*:*:*

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