Patch tracker / CVE reference / CVE-2026-21260
CVE-2026-21260
CVE-2026-21260 is a high severity Microsoft vulnerability with a CVSS score of 7.5. Microsoft has shipped the fix: deploy one of the 6 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
High severity Microsoft vulnerability, CVSS 7.5. Fixed by 6 Microsoft security updates.
Risk summary
Senserva AI Opinion for CVE-2026-21260
Labeled a Microsoft Outlook spoofing vulnerability but with an affected list spanning SharePoint Enterprise Server 2016, SharePoint Server 2019, and Office 2019, this High Severity CVSS 7.5 flaw touches both server and client sides of the Office estate. Spoofing bugs in mail and collaboration software are phishing enablers: they let attackers dress malicious content in trusted branding or origins. Exploit probability is 4 percent.
Do this: Apply the fix to on-premises SharePoint 2016 and 2019 farms and push the Office 2019 client update in the same wave.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-21260
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Updated August 7, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Full tracking and change history for CVE-2026-21260
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
Exploitation and severity
Not in the CISA KEV catalog. EPSS exploit probability 3.6%. CVSS 7.5 (High).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2026-21260
Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing updates KB5002833, KB5002834, KB5002836, KB5002839, KB5002840, KB5002841 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-2026-21260. 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.
Affected products
Fixed by the same updates
If you are patching CVE-2026-21260, the same updates also fix these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.