CVE-2021-42237 kev+ ransomware in the critical feed json
Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to ach…
published 2021-11-05 5 y ago modified 2026-07-09 4 mo ago also EUVD-2021-29215
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Exploited
- added 2022-03-25, used in ransomware
- epss
- 97.6%
- EPSS 97.6% chance of exploitation in 30 days, percentile 99.9%
- public exploits
- 1
- Metasploit, plus a Nuclei check
Summary
Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.
Patch / fix
cisa required action Apply updates per vendor instructions.
Timeline
- First public exploit (Metasploit exploit/windows/http/sitecore_xp_cve_2021_42237)
- Published
- Added to CISA KEV
- CISA patch deadline
- CISA SSVC: exploitation active
Known exploited
- Added
- 4 y ago
- Patch by
- 2022-04-15 (4 y ago)
- Ransomware
- Known to be used in ransomware campaigns
- Required action
- Apply updates per vendor instructions.
- Vendor, product
- Sitecore, XP
- CISA name
- Sitecore XP Remote Command Execution Vulnerability
Ransomware
Groups reported to have exploited it in intrusions.
- Prophet Spider initial access broker
reported by secureworks.com
Ransomware Vulnerability Matrix by BushidoUK (github.com/BushidoUK/Ransomware-Vulnerability-Matrix), reformatted per CVE. CC BY 4.0
ATT&CK techniques
How it is exploited and what it leads to, in MITRE ATT&CK terms.
- T1059 Command and Scripting Interpreter primary impact
kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- yes
- Technical impact
- total
- Assessed
- 21 mo ago
Exploit prediction
97.57% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- Metasploit exploit/windows/http/sitecore_xp_cve_2021_42237 Sitecore Experience Platform (XP) PreAuth Deserialization RCE metasploit exploit, excellent rank, 2021-11-02
- Nuclei template Sitecore Experience Platform Pre-Auth RCE nuclei detection template
- blog.assetnote.io https://blog.assetnote.io/2021/11/02/sitecore-rce/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 10.0 | AV:N/AC:L/Au:N/C:C/I:C/A:C |
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
References
-
blog.assetnote.io
/2021/11/02/sitecore-rce/
exploit, third-party-advisory
-
support.sitecore.com
/kb?id=kb_article_view&sysparm_article=KB1000776
vendor-advisory
-
packetstormsecurity.com
/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.html
third-party-advisory, vdb-entry
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42237
government-resource, us-government-resource
Sources
- CVE List CVE-2021-42237
- NVD CVE-2021-42237
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.