CVE-2026-65660
HighExploitedPublic exploitImproper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
Published Aug 11, 2026 · Updated Oct 8, 2026
Key Facts
Patch immediately- CVE-2026-65660 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Sharepoint Server (Microsoft), Sharepoint Server 2016 (Microsoft), Sharepoint Server 2019 (Microsoft) and 2 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 24, 2026. Public exploit code is available.
- EPSS estimates a 2.1% probability of exploitation in the next 30 days.
- Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5565.1001, Sharepoint Server 16.0.19725.20522, Sharepoint Server 2019 16.0.10417.20198.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
EPSS (30-day exploit likelihood)
2.1%
Higher than 81.4% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-65660 brief as a PDF
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Description
Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Sep 25, 2026 | Sep 28, 2026 | Not reported |
| Industry KEV feed | Sep 24, 2026 | Sep 28, 2026 | Not reported |
| CIRCL KEV | Sep 24, 2026 | Sep 28, 2026 | Not reported |
| ENISA EUVD | Sep 25, 2026 | n/a | Not reported |
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Affected Products
9 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Sharepoint ServerMicrosoft | 2016, 2019 | 16.0.19725.20522 |
| Sharepoint Server 2016Microsoft | See advisory | 16.0.5565.1001 |
| Sharepoint Server 2019Microsoft | >= 16.0.0 | 16.0.10417.20198 |
| Microsoft SharePoint Enterprise Server 2016 | >= 16.0.0 | 16.0.5565.1001 |
| Microsoft SharePoint Server Subscription Edition | >= 16.0.0 | 16.0.19725.20522 |
Patched Releases
Microsoft SharePoint Enterprise Server 2016
16.0.5565.1001
Sharepoint Server
16.0.19725.20522
Sharepoint Server 2019
16.0.10417.20198
Microsoft SharePoint Server Subscription Edition
16.0.19725.20522
Timeline
Publicly disclosed
Aug 11, 2026
Added to Industry KEV feed
Sep 24, 2026
Added to CIRCL KEV
Sep 24, 2026
Added to CISA KEV
Sep 25, 2026
Added to ENISA EUVD
Sep 25, 2026
Last updated
Oct 8, 2026
Weakness Type
- CWE-94 Improper Control of Generation of Code ('Code Injection')
References
- advisoryhttps://blog.previdian.com/cve-2026-65660-previdian-observes-two-stage-sharepoint-exploitation-attempts/
- advisory5002893
- advisory5002894
- advisory5002896
- advisory5002905
FAQ
Common Questions.
Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Affected: Sharepoint Server (Microsoft) versions 2016, 2019; Sharepoint Server 2016 (Microsoft); Sharepoint Server 2019 (Microsoft) versions >= 16.0.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 24, 2026.
Yes. It was added on Sep 25, 2026 with a federal remediation due date of Sep 28, 2026.
Public exploit code is available.
Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5565.1001, Sharepoint Server 16.0.19725.20522, Sharepoint Server 2019 16.0.10417.20198.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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