SRC-2020-0021 : Microsoft SharePoint Server SPHashtagHelper MakeOLSGetRequest Server-Side Request Forgery Information Disclosure Vulnerability



CVSS Score:

8.9, (/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L/E:P/RL:O/RC:C)

Affected Vendors:


Affected Products:

SharePoint Server

Vulnerability Details:

This vulnerability allows remote attackers disclose information and/or escalate privileges under certain conditions. Authentication is required to exploit this vulnerability.

The specific flaw exists within the CallOLS function inside of the SPHashtagStoreManager class. The issue results from the lack of proper validation of user-supplied url parameter when performing web requests. An attacker can leverage this vulnerability to execute arbitrary web requests to protected resources.

Vendor Response:

Microsoft has issued an update to correct this vulnerability. More details can be found at:

Disclosure Timeline:

  • 2020-07-06 – Sent to Microsoft
  • 2020-09-08 – Coordinated public release of advisory


This vulnerability was discovered by Steven Seeley (mr_me) of Qihoo 360 Vulcan Team