CVE-2026-40358 json
Microsoft Office Remote Code Execution Vulnerability
published 2026-05-12 5 mo ago modified 2026-10-26 13 d ago also EUVD-2026-29640
- cvss
- 8.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
Patch / fix
- Microsoft Microsoft Office 2016 16.0.5552.1000
- Microsoft Microsoft Office LTSC for Mac 2021 16.109.26051019
- Microsoft Microsoft Office LTSC for Mac 2024 16.109.26051019
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C |
| CNA | 3.1 | 8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- Microsoft Microsoft 365 Apps for Enterprise
- Microsoft Microsoft Office 2016
- Microsoft Microsoft Office 2019
- Microsoft Microsoft Office LTSC 2021
- Microsoft Microsoft Office LTSC 2024
- Microsoft Microsoft Office LTSC for Mac 2021
- Microsoft Microsoft Office LTSC for Mac 2024
Classification
- Weakness
-
- CWE-416 Use After Free
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-40358
vendor-advisory, patch
Sources
- CVE List CVE-2026-40358
- NVD CVE-2026-40358
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.