Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft — Microsoft SharePoint Enterprise Server 2016
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
9.8
77.0%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- Jul 14, 2026
- Modified
- Jul 23, 2026
- Added to KEV
- Jul 22, 2026
- Federal patch due
- Jul 25, 2026
CISA required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
5 foundWeaponization
Public repositories whose name or description references CVE-2026-50522, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
- 4minx/CVE-2026-50522★ 40
CVE-2026-50522 PoC
updated Aug 20, 2026
- WismanSec/sharepoint-2026-poc★ 2
PoC, IOCs, and detection logic for the SharePoint /_trust WS-Federation BinaryFormatter deserialization chain. Lab reconstruction covering unauthenticated RCE, in-process machine key theft, and the artifacts each variant leaves behind. SharePoint 2016, 2019, and Subscription Edition. CVE-2026-50522, CVE-2026-45659, CVE-2026-56164, CVE-2026-58644.
updated Aug 19, 2026
- HORKimhab/CVE-2026-50522★ 0
CVE-2026-50522
updated Aug 24, 2026
- darses/CVE-2026-50522★ 0
Microsoft SharePoint CVE-2026-50522
updated Jul 30, 2026
- ChPratik/CVE-2026-50522★ 0
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
updated Jul 27, 2026
References
Frequently asked questions
What is CVE-2026-50522?
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
How severe is CVE-2026-50522?
CVE-2026-50522 has a CVSS base score of 9.8 out of 10 (CVSS 3.1).
Is CVE-2026-50522 actively exploited in the wild?
Yes. CVE-2026-50522 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jul 22, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2026-50522?
77.0% - meaning FIRST.org's EPSS model estimates a 77.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2026-50522?
We found 5 public GitHub repositories referencing CVE-2026-50522, though none matched a known Nuclei template or Metasploit module at last check. Review each one before relying on it - see the proof-of-concept section above.
What type of vulnerability is CVE-2026-50522?
CVE-2026-50522 is classified under CWE-502 (CWE-502: Deserialization of Untrusted Data).
Cross-checked against
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