Unauthenticated code execution via unsafe XML deserialization
Published Mar 6, 2019 · Updated Oct 21, 2025
XML deserialization in affected Microsoft SharePoint releases allows remote attackers to execute arbitrary code through crafted picker data. The EntityInstanceIdEncoder classes in Microsoft.SharePoint.dll and Microsoft.SharePoint.Portal.dll pass attacker-controlled hiddenSpanData-derived type and object data to XmlSerializer without validating trusted types. Internet-facing Picker.aspx paths can reach this operation without authentication, and successful exploitation runs code in the SharePoint server process context.
Summary
What happened
XML deserialization in affected Microsoft SharePoint releases allows remote attackers to execute arbitrary code through crafted picker data. The EntityInstanceIdEncoder classes in Microsoft.SharePoint.dll and Microsoft.SharePoint.Portal.dll pass attacker-controlled hiddenSpanData-derived type and object data to XmlSerializer without validating trusted types. Internet-facing Picker.aspx paths can reach this operation without authentication, and successful exploitation runs code in the SharePoint server process context.
The record
- CVE
- CVE-2019-0604
- Published
- Mar 6, 2019
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Microsoft SharePoint Server
- Classifications
- CWE-20, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 6, 2019CVE publishedPublication date reported by the CVE source.
- May 6, 2019Exploitation reportedMalicious actors implanted web shells through SharePoint exploitation
- Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2010 Service Pack 2
- Affected versionversion=2019
What conditions does exploitation require?
What is affected?
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.
Public exploit references
- Microsoft SharePoint Deserialization Remote Code Executionfunctional · validated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Malicious actors implanted web shells through SharePoint exploitationreported exploitation
- CISA Known Exploited Vulnerabilities Catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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