CVE-2026-70321: Microsoft SharePoint 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 Microsoft Office SharePoint allows authorized attackers to execute code over the network.
- Who is affected
- SharePoint deployments accessible to authorized users are affected.
- Urgency
- High—CVSS 8.8 remote code execution; requires authorized access but poses significant risk.
- Action
- Apply patches for CVE-2026-70321 to Microsoft SharePoint immediately.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch SharePoint
Get an email when a new SharePoint advisory drops — max one per day, one-click unsubscribe.
Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70321
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-2026-703211.3% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 67% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-70321 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
More from Microsoft Security Response Center
- highCVE-2026-70130: Microsoft Office Remote Code Execution Vulnerability2026-08-11
- highCVE-2026-70354: .NET Core Remote Code Execution Vulnerability2026-08-11
- highCVE-2026-68792: Microsoft Office Elevation of Privilege Vulnerability2026-08-11
- highCVE-2026-66807: Microsoft Office Graphics Component Remote Code Execution Vulnerability2026-08-11
- highCVE-2026-64909: Microsoft Office Remote Code Execution Vulnerability2026-08-11