Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
Sitecore CMS and Experience Platform (XP) contain a deserialization vulnerability in the Sitecore.Security.AntiCSRF module that allows an unauthenticated attacker to execute arbitrary code by sending a serialized .NET object in the HTTP POST parameter __CSRFTOKEN.
- Vendor
- Sitecore
- Product
- CMS and Experience Platform (XP)
- CVSS
- 9.8
- EPSS (exploit probability)
- 83.7%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2019-9874 being exploited?
Yes. CISA added CVE-2019-9874 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 83.7% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-24. Full cross-catalog view: /kev-comparison
CVE-2019-9874 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Sitecore CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2025-53690 Sitecore Multiple Products Deserialization of Untrusted Data Vulnerability | [ CRITICAL ] | 9.0 | 60.6% | |
| CVE-2019-9875 Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability | [ HIGH ] | 8.8 | 13.8% | |
| CVE-2021-42237 Sitecore XP Remote Command Execution Vulnerabilityransomware use | [ CRITICAL ] | 9.8 | 97.6% |