Deserialization in Microsoft Sharepoint Enterprise Server 2016

CVE-2025-53770

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 a…

Vulnerability class: Insecure Deserialization

EPSS: 0.885 (99.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:W/RC:C.

Affected products

Weakness classification (CWE)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: .

Required action: Disconnect public-facing versions of SharePoint Server that have reached their end-of-life (EOL) or end-of-service (EOS) to include SharePoint Server 2013 and earlier versions. For supported versions, please follow the mitigations according to CISA (URL listed below in Notes) and vendor instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Known ransomware campaign use: yes.

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-53770?
CVE-2025-53770 is a critical-severity vulnerability in Microsoft Sharepoint Enterprise Server 2016, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2025-07-20.
How severe is CVE-2025-53770?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-53770 known to be exploited?
Yes. CVE-2025-53770 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-07-20), indicating it is being actively exploited. 108 public proof-of-concept repositories are indexed.