Microsoft released an advisory for CVE-2025-53770, a critical Remote Code Execution (RCE) vulnerability affecting on-premise SharePoint servers. This vulnerability has been exploited in the wild as a zero-day by an unknown threat actor prior to the disclosure from Microsoft.
The vulnerability is described as an unauthenticated deserialization of untrusted data issue, and has a CVSS base score of 9.8 (Critical). This vulnerability is being used in widespread, aggressive campaigns to achieve RCE, establish persistent access, and extract cryptographic keys that allow attackers to forge valid authentication tokens. This campaign is not opportunistic – it is deliberate, capable, and designed for persistence even after patching.
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Source: Rapid7
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