CVE-2026-21521

EUVD-2026-4498
Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.4 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
microsoftCNA
7.4 HIGH
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
Base Score
CVSS 3.x
EPSS Score
Percentile: 18%
Affected Products (NVD)
VendorProductVersion
microsoft365_word_copilot
-
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21521