Patch tracker / CVE reference / CVE-2026-55048
CVE-2026-55048
CVE-2026-55048 is a high severity Microsoft vulnerability with a CVSS score of 7.8. Microsoft has shipped the fix: deploy one of the 2 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 7.8. Fixed by 2 Microsoft security updates.
Risk summary
Updated July 25, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2026-55048
CVE-2026-55048 is a High severity (CVSS 7.8) remote code execution flaw reaching across Office Online Server and both 32-bit and 64-bit editions of Microsoft Office 2019, meaning both server-side document rendering and desktop Excel installs are in scope. RCE in Excel typically triggers when a user opens or previews a crafted spreadsheet, so mail gateways and file shares become delivery paths. It is not in CISA KEV and has no known ransomware use yet, but the wide install base of Office 2019 makes it an attractive target once exploit details circulate.
Do this: Deploy the Microsoft patch for CVE-2026-55048 to your Office Online Server and all Office 2019 (32-bit and 64-bit) endpoints, prioritizing systems that preview or open externally sourced spreadsheets.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-55048
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-55048
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 <1%. CVSS 7.8 (High).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2026-55048
Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing updates KB5002884, KB5002886 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-2026-55048. 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
Common questions about CVE-2026-55048
Is CVE-2026-55048 actively exploited?
It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the next 30 days at <1%.
What patch fixes CVE-2026-55048?
Microsoft fixed CVE-2026-55048 in KB5002884, KB5002886. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2026-55048?
Microsoft Office 2019 for 32-bit editions, Microsoft Office 2019 for 64-bit editions, Office Online Server.
Can I ask my own AI about CVE-2026-55048?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-55048's key facts: severity, CVSS, EPSS exploit probability, CISA KEV status, and the fixing KB. Copy it into Claude, ChatGPT, or Copilot for a triage plan; the data is refreshed twice a day (5 AM and 3 PM US Central).
Fixed by the same updates
If you are patching CVE-2026-55048, 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.
