Sitecore CMS and XP Deserialization Vulnerability (CVE-2019-9874)

Historical catalog analysis: CISA added this entry on March 26, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2019-9874 is a deserialization vulnerability (CWE-502) located within the Sitecore.Security.AntiCSRF module of Sitecore CMS and Experience Platform (XP). The flaw allows an unauthenticated attacker to execute arbitrary code on the target system by submitting a specially crafted serialized .NET object through the __CSRFTOKEN HTTP POST parameter.

Exposure and applicability

This vulnerability affects organizations deploying Sitecore CMS or Sitecore XP. Because the attack vector utilizes a standard HTTP POST parameter (__CSRFTOKEN) and does not require authentication, any instance of these platforms with the affected module exposed to untrusted network traffic is potentially susceptible. Infrastructure owners should prioritize assets that are internet-facing or reside in zones where unauthenticated requests can reach the Sitecore application server.

Remediation priorities

Based on the inclusion of this vulnerability in CISA’s Known Exploited Vulnerabilities (KEV) catalog, remediation should be treated as a high priority. Our analysis suggests the following prioritization:

1. Immediate Patching: Apply vendor-supplied mitigations and updates specifically addressing the Sitecore.Security.AntiCSRF module.
2. Cloud Configuration Review: For organizations utilizing Sitecore via cloud services, review configurations in accordance with BOD 22-01 guidance to ensure provider-side mitigations are active.
3. Decommissioning: If vendor mitigations are unavailable for a specific legacy version in use, the product should be discontinued to eliminate the exposure path.

How to validate remediation

Verification must go beyond a simple version check, as the presence of a specific software version does not inherently prove that the necessary security configurations or patches were successfully applied and initialized.

To verify that exposure has been reduced, defenders should:
* Confirm Patch Application: Audit system logs and installation records to ensure vendor-specific fixes for CVE-2019-9874 are deployed.
* Validate Input Handling: Use authorized security testing to confirm that the __CSRFTOKEN parameter no longer accepts or processes malicious serialized .NET objects.
* Configuration Audit: Verify that the Sitecore.Security.AntiCSRF module is operating under the updated, secure logic defined by the vendor.

Limits and open questions

While patching reduces the likelihood of exploitation, residual risk may remain if other deserialization vectors exist within the environment or if the patch is bypassed by new techniques. It remains unknown whether this vulnerability has been utilized in specific ransomware campaigns. Furthermore, while CISA has established a remediation deadline of April 16, 2025, for federal agencies, non-federal organizations must determine their own urgency based on their specific risk profile and exposure.

Source and editorial note

CVE-2019-9874: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability · Source date: March 26, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: March 29, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 20, 2026 at 00:22 UTC.

Request a Vulnerability Assessment