Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
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.
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 3 / 5
- KEV catalog (CISA)26 Mar 2025
- Exploited in EUVD (ENISA)26 Mar 2025
- Used by ransomwareno
- EPSS above 10 %25.4%
- No account, over the networkno
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Affected products
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
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EPSS peak: 25.4%
References
Other exploited vulnerabilities from the same vendor
- CVE-2025-53690Sitecore Multiple Products Deserialization of Untrusted Data Vulnerability7.8 · Background exploitation
- CVE-2019-9874Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability8.8 · Background exploitation
- CVE-2021-42237Sitecore XP Remote Command Execution Vulnerability9.8 · Background exploitation