CVSS base score: 9.8 (Critical) 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.
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Vendor: Microsoft Product: SharePoint
Microsoft SharePoint Server on-premises contains a deserialization of untrusted data vulnerability that could allow an unauthorized attacker to execute code over a network. This vulnerability could be chained with CVE-2025-53771. CVE-2025-53770 is a patch bypass for CVE-2025-49704, and the updates for CVE-2025-53770 include more robust protection than those for CVE-2025-49704.
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 100.0% on 2026-08-29.
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.
| Date | Source | Article |
|---|---|---|
| 2026-08-26 | Kaspersky Securelist | Exploits and vulnerabilities in Q2 2026 |
Articles from monitored vendor research blogs and security news feeds that specifically mention this CVE. Coverage begins when feed monitoring started; earlier articles are not indexed.
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 SharePoint Server Remote Code Execution Vulnerability
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 →
Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-502) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.
| Source | Date | Record |
|---|---|---|
| CISA KEV | 2025-07-20 | source record → |
| CISA Vulnrichment | 2025-08-18 | source record → |
| Date | Advisory | Issuer |
|---|---|---|
| 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 |
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.