CVE-2025-21361: Microsoft Outlook Remote Code Execution Vulnerability
CVE-2025-21361 is a remote code execution vulnerability in Microsoft Outlook, 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 0.78% probability of exploitation activity in the next 30 days, higher than 56% of all scored vulnerabilities. Microsoft released the fix on 14 January 2025 in the January 2025 Patch Tuesday. It affects 3 products in 1 product family (Microsoft Office).
Key facts
- CVE ID
- CVE-2025-21361
- 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-641
- EPSS
- 0.78% (percentile 56%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- January 2025 Patch Tuesday
- Product families
- Microsoft Office
CVSS score and vector
Microsoft scores CVE-2025-21361 at 7.8 (temporal 7.1) 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/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 |
| Report confidence | Confirmed |
Frequently asked questions (Microsoft)
How could an attacker exploit this vulnerability?
The attacker would be able to bypass the protection in Outlook that prevents a potentially dangerous file extension from being attached enabling a remote code execution.
Which version of Outlook for Mac does this affect?
This vulnerability only affects the Legacy version of Outlook for Mac which is described in this documentation: Outlook for Mac. Customers who have enabled the new Outlook experience are not affected.
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.
For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.
Is the Attachment Preview Pane an attack vector for this vulnerability?
Yes. The attachment Preview Pane that is accessed when a user clicks to preview an attached file is an attack vector; however, the email Preview Pane itself is not.
Affected products (3)
Microsoft Office
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Microsoft Office LTSC for Mac 2021 | Release Notes | Security Update | 16.93.25011212 | Yes |
| Microsoft Outlook for Mac | ||||
| Microsoft Office LTSC for Mac 2024 | Release Notes | Security Update | 16.93.25011212 | Yes |
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 7.8 (HIGH)
- NVD weakness
- CWE-641
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| office 2024 | all listed versions |
| office long term servicing channel 2021 | all listed versions |
| outlook | before 16.93 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21361 (Patch, Vendor Advisory)
Acknowledgments
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |