Remote Code Execution in Microsoft SharePoint via Deserialization of Untrusted Data
CVE-2026-45659 is a remote code execution vulnerability in Microsoft Office SharePoint caused by deserialization of untrusted data. The issue affects on-premises SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. According to the provided content, an authenticated attacker with minimal privileges, including Site Member-level permissions, can send specially crafted data to a vulnerable SharePoint server and trigger unsafe deserialization, causing the server to process attacker-controlled serialized input and execute arbitrary code over the network. Exploitation does not require administrator privileges, user interaction, or special environmental conditions, and Microsoft assigned the issue a CVSS score of 8.8.
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Impact, mitigation & remediation
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Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
No valid public exploits. Mallory filtered out 3 candidates as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
68 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A high-severity remote code execution vulnerability in Microsoft SharePoint caused by deserialization of untrusted data. It can be exploited by an authenticated attacker with low privileges over the network.
Remote code execution vulnerability in Microsoft SharePoint Server caused by deserialization of untrusted data; exploitable by an authenticated low-privilege user with Site Member-level access.
A remote code execution vulnerability in Microsoft SharePoint Server caused by deserialization of untrusted data, exploitable by authenticated users with Site Member-level permissions.
A high-severity remote code execution vulnerability in Microsoft SharePoint caused by deserialization of untrusted data. It can be exploited by an authenticated attacker with low attack complexity and requires no user interaction.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.