CVE-2026-48580: Microsoft Excel untrusted pointer dereference information disclosure

CVE-2026-48580 · Severity: medium · CVSS 5.5 · Published 2026-07-14

A security vulnerability exists in Microsoft Excel, the widely used spreadsheet application. An attacker could exploit this flaw to gain unauthorized access to sensitive information stored on a user's computer. To be successful, the attacker must convince a user to open a specially crafted file.

Technologies: Microsoft 365 Apps for Enterprise, Microsoft Excel 2016, Microsoft Office 2019, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, Microsoft Office LTSC for Mac 2024, Microsoft Office Online Server. Vendors: Microsoft.

Quick answers

Is CVE-2026-48580 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-48580 being exploited in the wild.
How severe is CVE-2026-48580?
Medium severity, with a CVSS score of 5.5, published 14 July 2026.
Which products and versions are affected?
Microsoft 365 Apps for Enterprise < 16.0.1; Microsoft Excel 2016 < 16.0.5561.1001; Microsoft Office 2019 < 19.0.0; Microsoft Office 365 for Mac < 16.111.26071215; and 5 more.
Is there a fix for CVE-2026-48580?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-48580 attacked?
It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-48580?
Check whether you run Microsoft 365 Apps for Enterprise, Microsoft Excel 2016, Microsoft Office 2019 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An untrusted pointer dereference vulnerability (CWE-822) exists in Microsoft Office Excel. The flaw is triggered when the application processes a specially crafted file containing malicious pointer data. An attacker can exploit this by convincing a local user to open the malicious file, leading to unauthorized information disclosure from the system's memory. The vulnerability affects multiple versions of Office, including Microsoft 365 Apps, Excel 2016, and Office LTSC for both Windows and Mac. Microsoft has released security updates to address this issue.

Affected products

  • Microsoft Microsoft 365 Apps for Enterprise < 16.0.1
  • Microsoft Microsoft Excel 2016 < 16.0.5561.1001
  • Microsoft Microsoft Office 2019 < 19.0.0
  • Microsoft Microsoft Office 365 for Mac < 16.111.26071215
  • Microsoft Microsoft Office LTSC 2021 < 16.0.1
  • Microsoft Microsoft Office LTSC 2024 < 16.0.0
  • Microsoft Microsoft Office LTSC for Mac 2021 < 16.0.1
  • Microsoft Microsoft Office LTSC for Mac 2024 < 16.0.0
  • Microsoft Office Online Server < 16.0.10417.20175

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory

References

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