Sitecore XP Remote Command Execution Vulnerability
Sitcore XP contains an insecure deserialization vulnerability which can allow for remote code execution.
- Vendor
- Sitecore
- Product
- XP
- CVSS
- 9.8
- EPSS (exploit probability)
- 97.6%
- Status
- kevransomware use
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-42237 being exploited?
Yes. CISA added CVE-2021-42237 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. CISA marks it as known to be used in ransomware campaigns.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 97.6% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-24. Full cross-catalog view: /kev-comparison
CVE-2021-42237 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 updates per vendor instructions.
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-2019-9874 Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability | [ CRITICAL ] | 9.8 | 83.7% |