MicrosoftRadarIndependent status for Microsoft services

Word Copilot Information Disclosure Vulnerability

CVE-2026-21521 is an information disclosure vulnerability in Microsoft Copilot (rated Critical, CVSS 7.4). Microsoft fixed it in the service; customers need to do nothing.

1 version

Facts

Microsoft id
CVE-2026-21521
Products
Microsoft Copilot
Severity
Critical
Impact
Information Disclosure
CVSS
7.4
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N/E:U/RL:O/RC:C
Exploited
No
Publicly disclosed
No
Customer action required
No
Release
2026-Jan
Assigned by
Microsoft
Weakness
CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences
MSRC revision
1.0
Status pages
Microsoft Copilot status
First captured by us
(from our first import of this list)
Microsoft last modified
Source
Security updates · open the original at Microsoft

Microsoft's revision notes

  1. Revision 1.0, 2026-01-22: Information published.

Microsoft says

Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.

Security updates,

Read Microsoft's full post

What Microsoft changed

One version so far. If Microsoft edits it, each change shows here with what was removed and added.

  1. First version we captured ·

    The text as we first saw it

    Seen by us · Microsoft's timestamp · Microsoft's page

Other changes for Microsoft Copilot