HighVulnerability

CVE-2026-21520: Copilot Studio exposure of sensitive information to unauthorized actor

Source: NVD(opens in a new tab)
Identifier: CVE-2026-21520
Published: January 22, 2026
Record updated: October 9, 2026

Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 1.5%

Summary

CVE-2026-21520 is an exposure of sensitive information to an unauthorized actor in Copilot Studio. According to the source, an unauthenticated attacker can view sensitive information through a network attack vector. The weakness is classified as CWE-77, Improper Neutralization of Special Elements used in a Command ('Command Injection'), and NVD has not yet provided an assessment.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Details

Scores and exploitation

CVSS score: 7.5(high)
EPSS: 1.5%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 4, 2026.

Weaknesses and techniques

Weakness (CWE): CWE-77
Attack pattern (CAPEC): CAPEC-88

Affected

Vendors: Microsoft

Classification

Attack type: Other
Attack sophistication: Moderate
AI component targeted: API
Impact: Confidentiality
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-21520

First tracked: February 15, 2026 at 08:51 PM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Topics

Coding assistants

Summary

Mitigation

Topics

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