CVE-2026-65660: Microsoft SharePoint Code Injection Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
Improper control of generation of code (‘code injection’) in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Description quoted from the CVE record (assigned by microsoft, published 2026-08-11).
Weakness: CWE-94: Improper Control of Generation of Code (‘Code Injection’)
How it can be exploited
Exploitable over the network with low attack complexity needing low privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. 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
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.
- On CISA KEV since
- 2026-09-25
- US federal deadline
- 2026-09-28
- Ransomware use
- Not known
Public exploit evidence (Exploit Observer)
Also known as: BDU:2026-15539, EUVD-2026-56431, GHSA-r94x-x846-rxqx
VEDAS cluster: VEDAS:BELTBIRD
Exploit Observer links 4 pieces of public exploit code or detection modules that name this CVE or one of its aliases.
Exploit code and modules (4)
Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.
- Code repository: https://github.com/shadowforge-cyber/cve-2026-65660-poc
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-65660.rules
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-65660.rules
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-65660.rules
Research and write-ups (2)
- Research or write-up: https://blog.previdian.com/cve-2026-65660-previdian-observes-two-stage-sharepoint-exploitation-attempts
- Research or write-up: https://blog.viettelcybersecurity.com/sharepoint_cve-2026-65660
Vulnerability databases and vendor advisories (6)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2026-56431
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-r94x-x846-rxqx
- Vulnerability database or vendor advisory: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-65660
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-65660
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-65660
- Vulnerability database or vendor advisory: https://www.tenable.com/cve/CVE-2026-65660
News (2)
- News: https://www.securityweek.com/microsoft-sharepoint-flaw-cve-2026-65660-now-exploited-in-attacks
- News: https://www.securityweek.com/microsoft-sharepoint-flaw-cve-2026-65660-now-exploited-in-attacks/amp
50 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.082
some chance of attack soon - VEDAS
- 0.977
strong exploit evidence - On CISA KEV
- Yes, since 2026-09-25
- Detection rule
- Suricata
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Microsoft Microsoft SharePoint Enterprise Server 2016 | from 16.0.0 before 16.0.5565.1001 | Not stated |
| Microsoft Microsoft SharePoint Server 2019 | from 16.0.0 before 16.0.10417.20198 | Not stated |
| Microsoft Microsoft SharePoint Server Subscription Edition | from 16.0.0 before 16.0.19725.20522 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: microsoft sharepoint_server, microsoft_corp microsoft_sharepoint_enterprise_server_2016, microsoft_corp microsoft_sharepoint_server_2019, microsoft_corp microsoft_sharepoint_server_subscription_edition.
How to fix it
Fixed versions stated in the CVE record: 16.0.5565.1001, 16.0.10417.20198, 16.0.19725.20522.
CISA 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.
Vendor guidance:
- Microsoft SharePoint Server Remote Code Execution Vulnerability (vendor-advisory, patch)
How to detect it
Suricata rules (network detection)
1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-65660 Microsoft SharePoint ToolPane web part Register directive injection RCE. Add them to your Suricata rule set and reload.
Show the rules
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-65660 Microsoft SharePoint ToolPane web part Register directive injection RCE"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"ToolPane.aspx"; nocase; fast_pattern; content:"DisplayMode=Edit"; nocase; http.request_body; content:"Register"; nocase; content:"Assembly"; nocase; classtype:web-application-attack; reference:cve,CVE-2026-65660; reference:url,https://www.exploit.observer/?keyword=CVE-2026-65660&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=sharepoint&match=exact; sid:1093403; rev:1;)
CVE-2026-65660.rules on GitHub
References
Vendor advisories and patches
- Microsoft SharePoint Server Remote Code Execution Vulnerability (vendor-advisory, patch)
Exploits and technical analysis
- https://blog.previdian.com/cve-2026-65660-previdian-observes-two-stage-sharepoint-exploitation-attempts/ (third-party-advisory)
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-65660 (government-resource)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.