CVE-2026-63520: Microsoft SharePoint Server Remote Code Execution Vulnerability
Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
CSIRTS triage
- What
- Improper input validation in SharePoint Server permits remote code execution by unauthorized attackers.
- Who is affected
- Unauthorized attackers with network access to SharePoint Server instances.
- Urgency
- High severity and CVSS (8.1); unauthenticated RCE in SharePoint makes this a critical priority.
- Action
- Apply SharePoint Server security updates for CVE-2026-63520 immediately; prioritize as critical patch.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63520
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Moderate exploitation riskCVE-2026-635201.1% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 62% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-63520 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
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