Type Vulnerability
Microsoft is announcing the availability of the security updates for Microsoft Office for Mac.
Microsoft · Memory corruption
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network
CVE-2026-100212
What this means
This is rated high severity (8.8 out of 10). There is no confirmed exploitation of it yet. Ask IT whether Microsoft 365 Apps, Microsoft Microsoft 365 and Microsoft Office 2021, and 2 more are in your estate, and treat that as the priority.
Full vendor description
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
Scoring and exploitation
8.8/ 10
CVSS 3.1 base scoreHigh
Exploitable over the network without any account, but only if a user takes an action, such as opening a file or link. High impact on confidentiality, integrity and availability.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploitability
Longer bar: easier to attack
Attack vectorNetworkAV:N
Attack complexityLowAC:L
Privileges requiredNonePR:N
User interactionRequiredUI:R
ScopeUnchangedS:U
Impact
Longer bar: more harm
ConfidentialityHighC:H
IntegrityHighI:H
AvailabilityHighA:H
- ~0.9% estimated chance of attack in 30 daysModel estimate (): a probability signal, not confirmed exploitation
- Exploited in the wild
- Not confirmed in the
- Not reported
Weaknesses
CWE-416
Affected products ()
- Microsoft 365 Apps
- Microsoft Microsoft 365
- Microsoft Office 2021
- Microsoft Office 2024
- Microsoft Office Online Server
Show the raw CPE strings (10)
- cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*
- cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*
- cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:*
- cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:*
- cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:*
- cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:*
- cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x64:*
- cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:-:x86:*
- cpe:2.3:a:microsoft:office_2024:-:*:*:*:ltsc:macos:-:*
- cpe:2.3:a:microsoft:office_online_server:*:*:*:*:*:*:*:*
References
1 link from the CVE record, grouped by site; the vendor's advisory comes first.
msrc.microsoft.com1 linkVendor advisory
- CVE-2026-100212 (opens in a new tab)Patch · Vendor Advisory