Authenticated code execution via unsafe deserialization
Published Aug 11, 2026 · Updated Aug 25, 2026
SharePoint Server Subscription Edition before 16.0.19725.20522 allows remote authenticated users to execute code via unsafe deserialization. Microsoft has disclosed only that a SharePoint code path deserializes attacker-controlled data; public advisories do not identify the affected endpoint, feature, or serialization format. Exploitation requires authenticated network access, and the published impact reflects code execution in the vulnerable server context with high confidentiality, integrity, and availability impact.
Summary
What happened
SharePoint Server Subscription Edition before 16.0.19725.20522 allows remote authenticated users to execute code via unsafe deserialization. Microsoft has disclosed only that a SharePoint code path deserializes attacker-controlled data; public advisories do not identify the affected endpoint, feature, or serialization format. Exploitation requires authenticated network access, and the published impact reflects code execution in the vulnerable server context with high confidentiality, integrity, and availability impact.
The record
- CVE
- CVE-2026-70321
- Published
- Aug 11, 2026
- Updated
- Aug 25, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-502, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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