Authenticated code execution via unsafe deserialization
Published Aug 11, 2026 · Updated Aug 25, 2026
Deserialization of untrusted data in Microsoft SharePoint allows remote authenticated users to execute code over a network. Microsoft's public records identify affected SharePoint 2016, 2019, and Subscription Edition builds and classify the flaw as CWE-502, but they do not disclose the vulnerable endpoint, request path, or deserialization routine that processes attacker-controlled data. Microsoft's CVSS vector requires low privileges and no user interaction, so ordinary authenticated access to a reachable on-premises SharePoint farm is sufficient for full server-side code execution.
Summary
What happened
Deserialization of untrusted data in Microsoft SharePoint allows remote authenticated users to execute code over a network. Microsoft's public records identify affected SharePoint 2016, 2019, and Subscription Edition builds and classify the flaw as CWE-502, but they do not disclose the vulnerable endpoint, request path, or deserialization routine that processes attacker-controlled data. Microsoft's CVSS vector requires low privileges and no user interaction, so ordinary authenticated access to a reachable on-premises SharePoint farm is sufficient for full server-side code execution.
The record
- CVE
- CVE-2026-65658
- Published
- Aug 11, 2026
- Updated
- Aug 25, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-502
- 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 is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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