Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
Sitecore CMS and Experience Platform (XP) contain a deserialization vulnerability in the Sitecore.Security.AntiCSRF module that allows an authenticated attacker to execute arbitrary code by sending a serialized .NET object in the HTTP POST parameter __CSRFTOKEN.
A remote attacker, with a low-privilege account, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-04-16 under CISA BOD 22-01.
This is a Deserialization of Untrusted Data (CWE-502) vulnerability in Sitecore CMS and Experience Platform (XP). Deserialization of Untrusted Data in the anti CSRF module in Sitecore through 9.1 allows an authenticated attacker to execute arbitrary code by sending a serialized .NET object in an HTTP POST parameter. Exploitation requires remote network access, low attack complexity, a low-privilege authenticated account, and no user interaction required.
Probably yes if any of these apply:
Active exploitation documented in the wild. Threat-research write-up: https://www.synacktiv.com/ressources/advisories/Sitecore_CSRF_deserialize_RCE.pdf
Manual remediation steps
Apply the Vendor Patch
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.
CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
References
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References