CVE-2026-123390: Microsoft Office SharePoint Remote Code Execution Vulnerability

Versions reported by the vendor

Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.

• Microsoft Microsoft SharePoint Server Subscription Edition

  • 16.0.0 and later · before 16.0.20326.20136affected

Other highest-scoring records for the same primary product.

• CVE-2026-120002Microsoft SharePoint Server Elevation of Privilege Vulnerability
  39Monitor
• CVE-2026-80095Microsoft Office SharePoint Elevation of Privilege Vulnerability
  36Monitor
• CVE-2026-109464Microsoft Office SharePoint Remote Code Execution Vulnerability
  36Monitor

Published before and after this one in the same product

• ← EarlierCVE-2026-112736Nov 10, 2026 · Microsoft Office SharePoint Spoofing Vulnerability
  21Monitor
• ← EarlierCVE-2026-120000Nov 10, 2026 · Microsoft Office SharePoint Remote Code Execution Vulnerability
  30Monitor
• Later →CVE-2026-123391Nov 10, 2026 · Microsoft Office SharePoint Elevation of Privilege Vulnerability
  35Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1payload = sock.recv(65536)2job = pickle.loads(payload)

1payload = sock.recv(65536)2if not hmac.compare_digest(sign(payload), header_sig):3    raise PermissionError("invalid signature")4job = JobSchema.validate(json.loads(payload))

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.