CVE-2019-9875

What the flaw is

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.

Description as published by CISA. We have not independently reproduced it.

What CISA requires

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

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

2 public repositories referencing this CVE have been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

• packetinside/CISA_BOT
• ums91/CISA_BOT

Vendor advisories

• support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB0038556
• nvd.nist.gov/vuln/detail/CVE-2019-9875

Primary sources

• NVD entry — CVSS score, CPE list and references
• CISA KEV catalog — the source for this page
• CVE Record at cve.org