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7.8
CVE-2021-34478: Microsoft Office Remote Code Execution Vulnerability - Malicious Code Runs
CVE-2021-34478 · published 5 years ago
Summary
Microsoft Office has a security flaw that allows hackers to run malicious code on your computer. This can happen if you open a malicious document or attachment. To protect yourself, make sure to keep your Microsoft Office software up to date with the latest security patches.
What to do
- Update microsoft microsoft 365 apps for enterprise to version https://aka.ms/OfficeSecurityReleases or later.
- Update microsoft microsoft office 2019 to version https://aka.ms/OfficeSecurityReleases or later.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| microsoft | microsoft 365 apps for enterprise | < https://aka.ms/OfficeSecurityReleases |
| microsoft | microsoft office 2019 | < https://aka.ms/OfficeSecurityReleases |
| microsoft | 365_apps |
All versions
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:*:* |
| microsoft | office |
2019 cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:*:* |
Original advisory text
Microsoft Office Remote Code Execution Vulnerability
Microsoft Office Remote Code Execution Vulnerability
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34478
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-3447... Patch Vendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-1024/ Third Party Advisory VDB Entry
Internet-facing
14 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit (estimated)
- Gives an attacker full control (estimated)
Timeline
Published12 Aug 2021
Updated6 Oct 2026
First seen10 Aug 2026
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