Remote Code Execution in Microsoft SharePoint Server via Deserialization of Untrusted Data
CVE-2026-45659 is a remote code execution vulnerability in Microsoft Office SharePoint affecting on-premises SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. The flaw is caused by deserialization of untrusted data within SharePoint. According to the provided content, an authenticated attacker with low privileges, including Site Member-level permissions, can send specially crafted data to a vulnerable SharePoint server over the network and cause SharePoint to deserialize attacker-controlled input, resulting in arbitrary code execution in the server context. The issue does not require administrator privileges or user interaction, and Microsoft released out-of-band patches for the affected versions.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No valid public exploits. Mallory filtered out 4 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
84 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.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.