CVE-2026-58651: Microsoft Word Remote Code Execution Vulnerability
CVE-2026-58651 is a remote code execution vulnerability in Microsoft Word, rated Important by Microsoft, with a CVSS 3.1 base score of 7.8 (High). An attacker can exploit it by an attacker with local access, without any privileges and only if a user takes an action. Microsoft has not reported exploitation in the wild and rates exploitation as less likely. The EPSS model estimates a 0.47% probability of exploitation activity in the next 30 days, higher than 41% of all scored vulnerabilities. Microsoft released the fix on 11 August 2026 in the August 2026 Patch Tuesday. It affects 9 products in 1 product family (Microsoft Office).
Key facts
- CVE ID
- CVE-2026-58651
- Severity
- High CVSS 7.8
- Microsoft severity
- Important
- Impact
- Remote Code Execution
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- Weakness
- CWE-122
- EPSS
- 0.47% (percentile 41%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- August 2026 Patch Tuesday
- Product families
- Microsoft Office
CVSS score and vector
Microsoft scores CVE-2026-58651 at 7.8 (temporal 6.8) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | Required |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | High |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code locally.
Frequently asked questions (Microsoft)
According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. This means an attacker or victim needs to execute code from the local machine to exploit the vulnerability.
According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
An attacker must send a user a malicious Office file and convince them to open it.
Is the Preview Pane an attack vector for this vulnerability?
No, the Preview Pane is not an attack vector.
Affected products (9)
Microsoft Office
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Microsoft Office 365 for Mac | Release Notes | Security Update | 16.112.26081010 | Maybe |
| Microsoft 365 Apps for Enterprise for 32-bit Systems | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft 365 Apps for Enterprise for 64-bit Systems | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft Office LTSC for Mac 2021 | Release Notes | Security Update | 16.112.26081010 | Maybe |
| Microsoft Office LTSC 2021 for 64-bit editions | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft Office LTSC 2021 for 32-bit editions | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft Office LTSC 2024 for 32-bit editions | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft Office LTSC 2024 for 64-bit editions | Click to Run | Security Update | https://aka.ms/OfficeSecurityReleases | No |
| Microsoft Office LTSC for Mac 2024 | Release Notes | Security Update | 16.112.26081010 | Maybe |
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 7.8 (HIGH)
- NVD weakness
- CWE-122
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| 365 apps (x64) | all listed versions |
| 365 apps (x86) | all listed versions |
| microsoft 365 | all listed versions |
| office 2021 (x64) | all listed versions |
| office 2021 (x86) | all listed versions |
| office 2021 | all listed versions |
| office 2024 (x64) | all listed versions |
| office 2024 (x86) | all listed versions |
| office 2024 | all listed versions |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58651 (Vendor Advisory)
Acknowledgments
- 0ccbbf129444eb66344ccafb92b00df4
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |