CVE-2026-65658: Microsoft SharePoint Server Remote Code Execution Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
CSIRTS triage
- What
- Deserialization of untrusted data in SharePoint Server allows network-based code execution.
- Who is affected
- Authorized attackers with network access to SharePoint Server deployments.
- Urgency
- Critical severity (CVSS 8.8) but not currently exploited; immediate remediation is required.
- Action
- Apply Microsoft security patches for CVE-2026-65658 immediately.
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-2026-65658
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-2026-656581.1% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 64% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-65658 | 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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