What is CVE-2019-9875?

CVE-2019-9875 is a high-severity vulnerability in Sitecore Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2019-05-31.

How severe is CVE-2019-9875?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2019-9875 known to be exploited?

Yes. CVE-2019-9875 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-03-26), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.

Deserialization in Sitecore Cms

CVE-2019-9875

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.

Vulnerability class: Insecure Deserialization

Published 2019-05-31 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.138 (96.5th percentile), scored 2026-10-18.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 96.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.140 · newest: 0.138 · change: -0.002

Affected products

Sitecore Cms

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-03-26. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2025-04-16.

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

Public proof-of-concept exploits

References

dev.sitecore.net/Downloads.aspx (Product, Vendor Advisory)
www.synacktiv.com/blog.html (Third Party Advisory)
www.synacktiv.com/ressources/advisories/Sitecore_CSRF_deserialize_RCE.pdf (Exploit, Patch, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2019-9875?: CVE-2019-9875 is a high-severity vulnerability in Sitecore Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2019-05-31.
How severe is CVE-2019-9875?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2019-9875 known to be exploited?: Yes. CVE-2019-9875 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-03-26), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.