CVE-2026-21520
CVE-2026-21520 is a high-severity vulnerability in Microsoft Copilot Studio with a CVSS 3.x base score of 7.5. 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 7.5)
- EPSS exploit prediction: 1% (69th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-4504
- Weakness: CWE-77
- Affected product: Microsoft Copilot Studio
- Published:
- Last modified:
Description
Exposure of Sensitive Information to an Unauthorized Actor in Copilot Studio allows a unauthenticated attacker to view sensitive information through network attack vector
Frequently asked questions
- What is CVE-2026-21520?
- Exposure of Sensitive Information to an Unauthorized Actor in Copilot Studio allows a unauthenticated attacker to view sensitive information through network attack vector
- How severe is CVE-2026-21520?
- CVE-2026-21520 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
- Is CVE-2026-21520 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-21520?
- CVE-2026-21520 affects Microsoft Copilot Studio. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-21520?
- 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-2026-21520 have an EU (EUVD) identifier?
- Yes. CVE-2026-21520 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4504.
- When was CVE-2026-21520 published?
- CVE-2026-21520 was published on 2026-01-22 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:microsoft:copilot_studio:-:*:*:*:*:*:*:*
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