Copilot Studio Information Disclosure Vulnerability

published 2026-01-22 9 mo ago modified 2026-07-30 3 mo ago also EUVD-2026-4504

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.5%; EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits: 0; none known

Exposure of Sensitive Information to an Unauthorized Actor in Copilot Studio allows a unauthenticated attacker to view sensitive information through network attack vector

Patch / fix

links 1

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21520 advisory

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 9 mo ago (2026-01-24)

Exploit prediction

1.53% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C/CR:H/IR:L/AR:L
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

Microsoft Microsoft Copilot Studio

Classification

Weakness

CWE-77 Improper Neutralization of Special Elements used in a Command

References

msrc.microsoft.com /update-guide/vulnerability/CVE-2026-21520
vendor-advisory, patch

Sources

CVE List CVE-2026-21520
NVD CVE-2026-21520

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary