CVE-2026-57105: Microsoft Office SharePoint Spoofing Vulnerability
CVE-2026-57105 is a spoofing vulnerability in Microsoft Office SharePoint, rated Important by Microsoft, with a CVSS 3.1 base score of 8 (High). An attacker can exploit it remotely over the network, with low 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 0.62% probability of exploitation activity in the next 30 days, higher than 50% of all scored vulnerabilities. Microsoft released the fix on 11 August 2026 in the August 2026 Patch Tuesday, delivered through 3 security updates (KB5002894, KB5002896, KB5002893). It affects 2 products in 1 product family (Microsoft Office).
Key facts
- CVE ID
- CVE-2026-57105
- Severity
- High CVSS 8
- Microsoft severity
- Important
- Impact
- Spoofing
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- Weakness
- CWE-79
- EPSS
- 0.62% (percentile 50%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- August 2026 Patch Tuesday
- Product families
- Microsoft Office
CVSS score and vector
Microsoft scores CVE-2026-57105 at 8 (temporal 7) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | Low |
| 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
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
Frequently asked questions (Microsoft)
There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software?
Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.
According to the CVSS metric, user interaction is required (UI:R) and privileges required is low (PR:L). What does that mean for this vulnerability?
An authorized attacker must send the user a malicious link and convince the user to open it.
Affected products (2)
Microsoft Office
Security updates (3)
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 8 (HIGH)
- NVD weakness
- CWE-79
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| sharepoint server | before 16.0.19725.20522 |
| sharepoint server 2019 | all listed versions |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-57105 (Patch, Vendor Advisory)
Acknowledgments
- P1hcn
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |