CVE-2026-63516: Microsoft SharePoint Server Spoofing Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.
CSIRTS triage
- What
- Unsafe deserialization in SharePoint Server enables spoofing attacks by authorized attackers.
- Who is affected
- Authorized users on SharePoint Server deployments.
- Urgency
- Medium severity (6.5 CVSS); requires existing credentials but can spoof identity and content.
- Action
- Apply SharePoint Server security updates for CVE-2026-63516.
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-2026-63516
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-2026-635161.3% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 69% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-63516 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
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