CVE-2026-50522

Critical9.8Published on July 14, 2026

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

Actively exploited

  • In the CISA exploited-vulnerabilities catalogue since Jul 22, 2026
  • US federal agencies must remediate it by Jul 25, 2026 (BOD 22-01)
  • First attack observed 5 days after disclosure
  • Confirmed by sensors, not only by reports

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.

Source: CISA KEV · Sep 8, 2026 Sep 7, 2026 Sep 6, 2026 Sep 5, 2026 Sep 4, 2026 Sep 3, 2026

CVSS score9.8 / 10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)CWE-502
Vendorsmicrosoft

Affected products

VendorsProductVersions
microsoftsharepoint server< 16.0.19725.20434

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