How severe is CVE-2026-26133?

CVE-2026-26133 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2026-26133 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26133?

CVE-2026-26133 primarily affects Microsoft 365 Copilot. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-26133?

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

Does CVE-2026-26133 have an EU (EUVD) identifier?

Yes. CVE-2026-26133 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12111.

When was CVE-2026-26133 published?

CVE-2026-26133 was published on 2026-03-16 and last updated on 2026-06-17.

CVE-2026-26133

CVE-2026-26133 is a high-severity vulnerability in Microsoft 365 Copilot with a CVSS 3.x base score of 7.1. 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-77.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12111
Weakness: CWE-77
Affected product: Microsoft 365 Copilot
Published: 2026-03-16
Last modified: 2026-06-17

Description

AI command injection in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Frequently asked questions

What is CVE-2026-26133?: AI command injection in M365 Copilot allows an unauthorized attacker to disclose information over a network.
How severe is CVE-2026-26133?: CVE-2026-26133 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2026-26133 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26133?: CVE-2026-26133 primarily affects Microsoft 365 Copilot. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-26133?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-26133 have an EU (EUVD) identifier?: Yes. CVE-2026-26133 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12111.
When was CVE-2026-26133 published?: CVE-2026-26133 was published on 2026-03-16 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26133

Affected products (20)

cpe:2.3:a:microsoft:365_copilot:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:365_copilot:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:edge:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:edge:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:excel:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:excel:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:loop:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:onenote:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:onenote:-:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:outlook:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:outlook:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:outlook:-:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:power_bi:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:power_bi:-:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:powerpoint:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:powerpoint:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:teams:*:*:*:*:*:android:*:*
cpe:2.3:a:microsoft:teams:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:word:*:*:*:*:*:iphone_os:*:*
cpe:2.3:a:microsoft:word:*:*:*:*:*:android:*:*

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