CVE-2026-21259

Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to elevate privileges locally.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21259	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x64:*
	cpe:2.3:a:microsoft:365_apps:-::::enterprise::x86:*
	cpe:2.3:a:microsoft:excel:2016::::::x64:
	cpe:2.3:a:microsoft:excel:2016::::::x86:
	cpe:2.3:a:microsoft:office:2019::::::x64:
	cpe:2.3:a:microsoft:office:2019::::::x86:
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:::::-:x86:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x64:*
	cpe:2.3:a:microsoft:office_long_term_servicing_channel:2024:::::-:x86:*
	cpe:2.3:a:microsoft:office_online_server::::::::

History

No history.

Information

Published : 2026-02-10 18:16

Updated : 2026-02-11 19:12

NVD link : CVE-2026-21259

Mitre link : CVE-2026-21259

CVE.ORG link : CVE-2026-21259

JSON object : View

Products Affected

microsoft

excel
office
office_long_term_servicing_channel
office_online_server
365_apps

CWE

CWE-122

Heap-based Buffer Overflow

CWE-787

Out-of-bounds Write

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