Patch tracker / CVE reference / CVE-2026-45659
CVE-2026-45659
CVE-2026-45659 is a Microsoft vulnerability that Microsoft rates Important, with a CVSS score of 8.8 (High). It is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it in the wild, including in ransomware campaigns, which makes it a fix-first item. Microsoft has shipped the fix: deploy one of the 3 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Our data comes from Microsoft, CISA and other public sources, and it can be wrong or out of date. If you are unsure, check the linked source before you act, and tell us when we are wrong so we can fix it.
Microsoft rates it Important. CVSS 8.8 (High). Fixed by 3 Microsoft security updates.
Risk summary
Listed in the CISA Known Exploited Vulnerabilities catalog, confirmed exploited in the wild. EPSS exploit probability 80%. CVSS 8.8 (High). Linked to ransomware activity.
This CVE is among the top 5% of tracked Microsoft CVEs by EPSS exploit probability, and one of 2 actively-exploited CVEs in May 2026.
Drawn by Senserva Vivid from the Senserva change record. Hover any point for its date and value.
- 2026-07-01 added to the CISA KEV catalog by CISA
- 2026-07-17 EPSS first scored at 3.2%
- 2026-07-24 EPSS 3.2% to 9.1%
- 2026-07-27 EPSS 9.1% to 6.9%
- 2026-07-29 EPSS 6.9% to 9.1%
- 2026-08-10 linked to ransomware activity
- 2026-08-24 EPSS 9.1% to 76.1%
- 2026-10-25 EPSS 76.1% to 80.2%
Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.
CVE-2026-45659 is a SharePoint remote code execution flaw that CISA confirmed as exploited in the wild and added to its Known Exploited Vulnerabilities catalog on 2026-07-01, which matters more than its 7 percent EPSS score suggests. On-premises SharePoint Enterprise Server 2016, Server 2019, and Subscription Edition are all in scope, and these servers often sit deep in internal networks with broad access to documents and service accounts. Confirmed exploitation of a server that authenticated users touch daily makes this a priority even without ransomware attribution.
Do this: Apply Microsoft's patch for CVE-2026-45659 to all SharePoint 2016, 2019, and Subscription Edition servers now, per the KEV due date.
AI-generated from public data, 2026-07-26. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-45659
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Official patch(es) for CVE-2026-45659
Treat as urgent: it is being exploited in the wild (CISA KEV), so patch ahead of items that are not. In Intune or Defender, confirm whether the fixing updates KB5002863, KB5002868, KB5002870 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security updates below to fix CVE-2026-45659. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.
Scope and sources
- Affected products
- Fixed by the same updates
- Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.