Sitecore · CMS and Experience Platform (XP)

CVE-2019-9875

Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability

Exploited in attacks High 8.8 Attack chance: 25%

What it is

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.

CISA: 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.

What to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Deadline for US federal agencies: April 16, 2025

Added to the CISA list: March 26, 2025
Published: May 31, 2019
Severity: High 8.8 CVSS 3.1
Chance of attacks in the next 30 days (EPSS): 25% in the top 2.1% of all known vulnerabilities
Weakness: CWE-502
More details: NVD · CVE.org · CISA

All references (3)

More exploited flaws from Sitecore

Added	Vulnerability	Product	Severity	Attack chance
Mar 26, 2025	DeserializationCVE-2019-9874	CMS and Experience Platform (XP)	Critical 9.8	84%
Sep 4, 2025	Deserialization of Untrusted DataCVE-2025-53690	Multiple Products	Critical 9.0	61%
Mar 25, 2022	Remote Command ExecutionCVE-2021-42237used by ransomware	XP	Critical 9.8	98%

All of them →

Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.