CVE-2026-26129
Published: 07 May 2026
Summary
CVE-2026-26129 is a high-severity Improper Neutralization of Special Elements (CWE-138) vulnerability in Microsoft 365 Copilot Chat. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 19.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
This vulnerability is AI-related — categorised as Enterprise AI Assistants; in the Privacy and Disclosure risk domain.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-28445
Vulnerability details
Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.
- CWE(s)
AI Security AnalysisAI
- AI Category
- Enterprise AI Assistants
- Risk Domain
- Privacy and Disclosure
- OWASP Top 10 for LLMs 2025
- None mapped
- Classification Reason
- Matched keywords: m365 copilot
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CWE-138 injection flaw in public-facing M365 Copilot directly enables remote exploitation for information disclosure (T1190).
CVEs Like This One
Affected Assets
Mitigating Controls
No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.