Patch tracker / CVE reference / CVE-2026-45659

CVE-2026-45659

CVE-2026-45659 is a high severity Microsoft vulnerability with a CVSS score of 8.8. 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.

Risk summary

HighCISA KEVRansomware

8.8

CVSS

9.1%

EPSS, 30 days

High

Severity

Yes

Exploited in the wild

Listed in the CISA Known Exploited Vulnerabilities catalog, confirmed exploited in the wild. EPSS exploit probability 9.1%. CVSS 8.8 (High). Linked to ransomware activity.

This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability, and one of 1 actively-exploited CVEs in May 2026.

Senserva Watchevery change we have recorded for this one

What changed, and when

CISA confirmed active exploitation of CVE-2026-45659 on 2026-07-01, and its EPSS exploit probability moved from 3.2% to 9.1% by 2026-07-24.

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

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.

Senserva AI Opinion for CVE-2026-45659

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.

I am an IT admin assessing a vulnerability. Facts for CVE-2026-45659 (source: https://senserva.com/cve/CVE-2026-45659.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2026-45659: High severity Microsoft vulnerability, CVSS 8.8
- EPSS 30-day exploitation probability: 9.1%
- Actively exploited (CISA KEV): YES, ransomware-linked
- Fixed by: KB5002863, KB5002868, KB5002870
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) What to patch or mitigate first. 4) How to check whether my devices are exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch immediately

Exploited in the wild and used in ransomware campaigns.

Fixed by KB5002863 and 2 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Move this ahead of everything else in the queue, then verify the fix actually landed on every exposed device.

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.

KB5002863 KB5002868 KB5002870

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-33110 CVE-2026-33112 CVE-2026-35439 CVE-2026-40357 CVE-2026-40365 CVE-2026-40367 CVE-2026-40368 CVE-2026-47294

Authoritative references

Official CVE record (cve.org)NVD detail Microsoft MSRC CISA KEV catalog FIRST.org EPSS

Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.