Advisory Details

June 23rd, 2021

Microsoft SharePoint WorkflowCompilerInternal Exposed Dangerous Function Remote Code Execution Vulnerability

ZDI-21-755
ZDI-CAN-13349

CVE ID CVE-2021-26420
CVSS SCORE 7.5, (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
AFFECTED VENDORS Microsoft
AFFECTED PRODUCTS SharePoint
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft SharePoint. Authentication is required to exploit this vulnerability.

The specific flaw exists within the System.Workflow.ComponentModel.Compiler.WorkflowCompilerInternal class. This class allows an attacker to specify a path to an arbitrary workflow definition file. An attacker can leverage this vulnerability to execute code in the context of the web service account.

ADDITIONAL DETAILS Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26420
DISCLOSURE TIMELINE
  • 2021-03-26 - Vulnerability reported to vendor
  • 2021-06-23 - Coordinated public release of advisory
CREDIT Anonymous
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