CVE-2025-27218
📋 TL;DR
CVE-2025-27218 is an insecure deserialization vulnerability in Sitecore Experience Manager (XM) and Experience Platform (XP) that allows remote attackers to execute arbitrary code on affected systems. This affects organizations running vulnerable Sitecore versions before applying the security patch. Attackers can exploit this to gain control of the application server.
💻 Affected Systems
- Sitecore Experience Manager (XM)
- Sitecore Experience Platform (XP)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary code, steal sensitive data, deploy ransomware, or pivot to other internal systems.
Likely Case
Remote code execution leading to data theft, website defacement, or installation of backdoors for persistent access.
If Mitigated
Limited impact with proper network segmentation, WAF rules blocking deserialization attacks, and minimal privileges.
🎯 Exploit Status
Insecure deserialization vulnerabilities are commonly exploited once details become public. Attackers need to craft malicious serialized objects.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: KB1002844 for Sitecore 10.4
Vendor Advisory: https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1003535
Restart Required: Yes
Instructions:
1. Download KB1002844 from Sitecore support portal. 2. Backup your Sitecore instance. 3. Apply the hotfix following Sitecore's installation instructions. 4. Restart the application. 5. Verify the patch is applied correctly.
🔧 Temporary Workarounds
WAF Rule for Deserialization Attacks
allConfigure Web Application Firewall to block known deserialization attack patterns and suspicious serialized objects.
Network Segmentation
allIsolate Sitecore servers from internet and restrict access to trusted IP addresses only.
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted sources only.
- Deploy runtime application self-protection (RASP) or intrusion prevention systems to detect and block deserialization attacks.
🔍 How to Verify
Check if Vulnerable:
Check Sitecore version in Control Panel > System > About. If version is 10.4 and KB1002844 is not installed, the system is vulnerable.Check Version:
Check Sitecore Control Panel > System > About or examine web.config for version information.Verify Fix Applied:
Verify KB1002844 is listed in installed updates in Sitecore Control Panel or check version details.📡 Detection & Monitoring
Log Indicators:
- Unusual deserialization errors in Sitecore logs
- Suspicious .NET serialization activity
- Unexpected process creation from w3wp.exe
Network Indicators:
- HTTP requests containing serialized objects to Sitecore endpoints
- Unusual outbound connections from Sitecore servers
SIEM Query:
source="sitecore_logs" AND ("deserialization" OR "SerializationException" OR "BinaryFormatter")