CVE-2026-21521
published 2026-01-22CVE-2026-21521: Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.
PriorityP341high7.4CVSS 3.1
AVNACLPRNUIRSCCHINAN
EPSS
0.50%
39.2th percentile
Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | microsoft_365_word_copilot | — | — |
| msrc | microsoft_365_word_copilot | — | — |
CVSS provenance
nvdv3.17.4HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
vendor_msrc7.4HIGH
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Microsoft
Word Copilot Information Disclosure Vulnerability
vendor_msrc·2026-01-13·CVSS 7.4
CVE-2026-21521 [HIGH] CWE-150 Word Copilot Information Disclosure Vulnerability
Word Copilot Information Disclosure Vulnerability
Description: Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.
FAQ: Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability?
This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency.
Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.
Copilot: Copilot
Microsoft: Microsoft
Customer Action Required: No
Impact: Information Disclosure
Exploit Status: Publicly Disclosed:No;Exploited:No;Latest Software Release:N/A
GHSA
GHSA-mmfw-g245-wgx2: Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network
ghsa_unreviewed·2026-01-23
CVE-2026-21521 [HIGH] CWE-150 GHSA-mmfw-g245-wgx2: Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network
Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-01-22
Published