CVE-2025-53690 Sitecore Multiple Products Deserialization of Untrusted Data Vulnerability
Sitecore Experience Manager (XM), Experience Platform (XP), Experience Commerce (XC), and Managed Cloud contain a deserialization of untrusted data vulnerability involving the use of default machine keys. This flaw allows attackers to exploit exposed ASP.NET machine keys to achieve remote code execution.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 4 Sep 2025.
- Rated Critical severity (CVSS 9.0, scored by Vendor).
- It has been in the catalogue for 428 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Deserialization of Untrusted Data vulnerability in Sitecore Experience Manager (XM), Sitecore Experience Platform (XP) allows Code Injection.This issue affects Experience Manager (XM): through 9.0; Experience Platform (XP): through 9.0.
Affected Versions
| Product | Versions |
|---|---|
| Sitecore Experience Manager (XM) | 9.0 and earlier |
| Sitecore Experience Platform (XP) | 9.0 and earlier |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Sitecore Multiple Products. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2025-53690 and every other exploited flaw on the list.