CVE-2025-53770
Microsoft SharePoint: Deserialization of Untrusted Data
- Act now
- CVSS 9.8 Critical
- CISA KEV, due
- VulnCheck KEV
- ENISA exploited-vulnerability catalog
What it is
ReportedMicrosoft 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.
Dates
What is affected
ReportedMicrosoft; SharePoint. Product-level identification only; no affected-version conclusion is available from this field.
Dates
Urgency and basis
Tracker computedAct now
Current priority score and EPSS: loading from the tracker record. They are read when this page loads and are not shown without JavaScript. They change daily and are not part of "Source last updated".
Dates
Exploitation evidence
ReportedActive exploitation · CISA KEV · VulnCheck KEV · ENISA exploited-vulnerability catalog
Dates
What to do
ReportedDisconnect 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.
Source remediation ↗Dates
Detection and validation
Mapped metadata availability only. These signals do not change priority.
Sigma
Potential QBot Activity. Level: critical. Status: stable.
Open Sigma metadataAtomic
Abuse Nslookup with DNS Records. Executor: powershell. Elevation: not reported.
Open Atomic metadataNuclei
Microsoft SharePoint Server - Remote Code Execution (ToolShell). Check identifier: CVE-2025-53770.
Open Nuclei metadata
Evidence detail
Loading the full tracker evidence record…