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cve recordhighexploit reported

CVE-2026-63520

microsoft · sharepoint server

Published
CVSS8.1
Severityhigh
WeaknessCWE-20
EPSS0.96%61.0th percentile
Exploited1 KEV source

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

patch window

Called exploited 14 days after disclosure.

Measured from the CVE publication date to the earliest of 1 KEV catalogue that list it.

The life of this vulnerability

  1. CVE published
  2. First KEV listing14d
  3. Last sighting1d

Gaps are compressed to equal steps. The elapsed time is printed under each.

Which catalogues call it exploited

Sources1 of 3
Listings differ by—
Strongest claimconfirmed

This rests on a single catalogue. No second catalogue corroborates the claim that it is being exploited. CIRCL is an aggregator and is not counted.

Public exploitation evidence

2 public reports collected from VulnCheck and CIRCL, first on Aug 25, 2026. Each links to its original source. We have not verified them.

Description

Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

References

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Our coverage of CVE-2026-63520

CVE-2026-63520critical

Rapid7 Analysis: Microsoft SharePoint Remote Code Execution (CVE-2026-63520)

A remote code execution (RCE) vulnerability, identified as CVE-2026-63520, has been disclosed in Microsoft SharePoint, allowing an authenticated attacker to execute arbitrary code on a vulnerable server. When chained with an authentication bypass vulnerability, CVE-2026-55040, the exploit becomes unauthenticated.