CVE-2025-53770 CISA KEV — actively exploited Ransomware-linked

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Microsoft — Microsoft SharePoint Enterprise Server 2016

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.

CVSS scoreCritical

9.8

EPSS — exploitation probabilityCritical

100.0%

Vector breakdown

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published: Jul 20, 2025
Modified: Aug 4, 2026
Added to KEV: Jul 20, 2025
Federal patch due: Jul 21, 2025

CISA 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.

Weakness classification

CWE-502Deserialization of Untrusted Data

Affected packages

unknown packageunknown

GHSA-xcrc-8vqv-vc8r

Proof-of-concept & exploitation references

8 found

Weaponization

Nuclei template

Available

Metasploit module

Not found

Public repositories whose name or description references CVE-2025-53770, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

References

How this class of flaw gets exploited

Insecure Deserialization

Frequently asked questions

What is CVE-2025-53770?

How severe is CVE-2025-53770?

CVE-2025-53770 has a CVSS base score of 9.8 out of 10 (CVSS 3.1).

Is CVE-2025-53770 actively exploited in the wild?

Yes. CVE-2025-53770 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jul 20, 2025, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.

What is the EPSS score for CVE-2025-53770?

100.0% - meaning FIRST.org's EPSS model estimates a 100.0% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).

Is there exploit tooling available for CVE-2025-53770?

Yes - a public Nuclei template referencing CVE-2025-53770 exist in public repositories we checked. We also found 8 public GitHub repositories referencing this CVE.

What type of vulnerability is CVE-2025-53770?

CVE-2025-53770 is classified under CWE-502 (CWE-502: Deserialization of Untrusted Data).

Cross-checked against

Impactr finds and proves whether CVE-2025-53770 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.

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