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CVE-2025-53771

Exploitation: none CVSS 6.5 MEDIUM

CVSS base score: 6.5 (Medium) vendor CNA · v3.1

Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one.

Vendor: Microsoft   Product: Microsoft SharePoint Enterprise Server 2016

Description

Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

Lifecycle Timeline

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 73 points from 2025-07-26, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 99.9% on 2026-06-20.

Published Applicability

CVE List v5 (CNA container) 3 affected · 0 fixed · 0 not affected

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

No mentions found in monitored research blogs or news feeds.

Detection & Exploitation

Scan
Exploit / Pen Test
Network IDS/IPS
none published
Host / SIEM
none published

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

Microsoft Assessment

published by the affected vendor via MSRC

Microsoft SharePoint Server Spoofing Vulnerability

Exploitation Less Likely
No
No
Important
Spoofing
Microsoft Office SharePoint
2025-07-20

The vendor's own judgement about their own code, shown alongside CISA's rather than merged into it. The exploitability index is a forward-looking prediction, distinct from a CVSS severity or CISA's SSVC decision, and vendors often report observed exploitation before a CVE reaches the KEV catalog. Vendor advisory →

CISA Assessment (Vulnrichment / SSVC)

none
yes
partial
—
6.5 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C
CWE-287 — Improper Authentication
2025-07-21

D3FEND Countermeasures

Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-287) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.

Listed By

SourceDateRecord
CISA Vulnrichment 2025-07-21 source record →

Referenced in Advisories

DateAdvisoryIssuer
2025-08-06 CISA Releases Malware Analysis Report Associated with Microsoft SharePoint Vulnerabilities CISA
2025-08-06 MAR-251132.c1.v1 Exploitation of SharePoint Vulnerabilities CISA
2025-07-24 2025-027: Critical Vulnerabilities in Microsoft SharePoint CERT-EU
2025-07-20 UPDATE: Microsoft Releases Guidance on Exploitation of SharePoint Vulnerabilities CISA

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References