Risk Letters

Exploited vulnerability

CVE-2026-58644

TLP:CLEAR

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.

Facts

  • Vendor: Microsoft
  • Product: SharePoint
  • CVSS: 9.8
  • EPSS (probability of exploitation within 30 days): 15.9 %
  • On CISA's Known Exploited Vulnerabilities list since: 16 July 2026
  • First known exploitation: 16 July 2026
  • CISA's deadline for US federal agencies: 19 July 2026
  • Weakness: CWE-502
  • First seen by Risk Letters: 14 July 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD