CVE-2025-53770 KEV EXPLOIT
9.8
CRITICAL · CVSS 3.1 · EPSS 100% (pctl 100)
Patch first
On CISA KEV — known exploited in the wild, due 2025-07-21.
Description
Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to execute code over a network. Microsoft is aware that an exploit for CVE-2025-53770 exists in the wild. Microsoft is preparing and fully testing a comprehensive update to address this vulnerability. In the meantime, please make sure that the mitigation provided in this CVE documentation is in place so that you are protected from exploitation.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 100% — more likely to be exploited than 100% of all CVEs |
| Weakness | CWE-502 |
| On CISA KEV | yes — remediate by 2025-07-21 |
| Public exploit | yes |
| Published | 2025-07-20 |
| Last modified | 2026-08-04 |
CISA KEV
| Name | Microsoft SharePoint Deserialization of Untrusted Data Vulnerability |
|---|---|
| Added | 2025-07-20 |
| Due | 2025-07-21 |
| Vendor / product | Microsoft / SharePoint |
| Ransomware use | known |
Affected (1)
| Vendor | Product |
|---|---|
| microsoft | sharepoint server |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Microsoft SharePoint Server 2019 (16.0.10383.20020) - Remote Code Execution (RCE) | 2025-08-11 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770
- https://arstechnica.com/security/2025/07/sharepoint-vulnerability-with-9-8-severity-rating-is-under-exploit-across-the-globe/
- https://github.com/kaizensecurity/CVE-2025-53770
- https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/
- https://news.ycombinator.com/item?id=44629710
- https://research.eye.security/sharepoint-under-siege/
- https://therecord.media/microsoft-sharepoint-zero-day-vulnerability-exploited-globally
- https://www.bleepingcomputer.com/news/microsoft/microsoft-sharepoint-zero-day-exploited-in-rce-attacks-no-patch-available/
- https://www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770
- https://www.darkreading.com/remote-workforce/microsoft-rushes-emergency-fix-exploited-sharepoint-toolshell-flaw
- https://www.forbes.com/sites/daveywinder/2025/07/20/microsoft-confirms-ongoing-mass-sharepoint-attack---no-patch-available/
- https://x.com/Shadowserver/status/1946900837306868163
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53770
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