CVE-2021-39170
📋 TL;DR
CVE-2021-39170 is a stored cross-site scripting (XSS) vulnerability in Pimcore that allows authenticated users to inject malicious scripts into asset metadata fields. When other users view assets containing this malicious metadata, the scripts execute in their browser context. This affects all Pimcore installations prior to version 10.1.2 where users have asset management permissions.
💻 Affected Systems
- Pimcore
📦 What is this software?
Pimcore by Pimcore
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker could steal session cookies, perform actions as other users, deface the interface, or redirect users to malicious sites, potentially leading to full account compromise and data theft.
Likely Case
Attackers with legitimate user accounts could perform session hijacking, steal sensitive data displayed in the interface, or manipulate user sessions for privilege escalation.
If Mitigated
With proper input validation and output encoding, the XSS payloads would be rendered harmless as text rather than executable code.
🎯 Exploit Status
Exploitation requires authenticated access. The patch and advisory provide clear details about the vulnerable code path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.2
Vendor Advisory: https://github.com/pimcore/pimcore/security/advisories/GHSA-2v88-qq7x-xq5f
Restart Required: No
Instructions:
1. Update Pimcore to version 10.1.2 or later using your package manager or deployment method. 2. Verify the update completed successfully. 3. Clear any caches if applicable.
🔧 Temporary Workarounds
Manual patch application
linuxApply the security patch from GitHub without upgrading the entire Pimcore installation
curl -L https://github.com/pimcore/pimcore/pull/10178.patch | patch -p1
🧯 If You Can't Patch
- Restrict asset metadata editing permissions to only trusted administrators
- Implement web application firewall (WAF) rules to block XSS payloads in metadata fields
🔍 How to Verify
Check if Vulnerable:
Check if Pimcore version is below 10.1.2. Review if custom metadata fields on assets accept and execute JavaScript code without proper sanitization.Check Version:
php bin/console pimcore:versionVerify Fix Applied:
After patching, attempt to inject XSS payloads into asset metadata fields and verify they are properly sanitized and do not execute.📡 Detection & Monitoring
Log Indicators:
- Unusual metadata updates containing script tags or JavaScript code
- Multiple failed XSS attempts in metadata fields
Network Indicators:
- Unexpected outbound connections from Pimcore interface when viewing assets
SIEM Query:
source="pimcore" AND ("metadata" OR "asset") AND ("<script>" OR "javascript:" OR "onerror=" OR "onload=")🔗 References
- https://github.com/pimcore/pimcore/pull/10178
- https://github.com/pimcore/pimcore/pull/10178.patch
- https://github.com/pimcore/pimcore/security/advisories/GHSA-2v88-qq7x-xq5f
- https://huntr.dev/bounties/e4cb9cd8-89cf-427c-8d2e-37ca40099bf2/
- https://github.com/pimcore/pimcore/pull/10178
- https://github.com/pimcore/pimcore/pull/10178.patch
- https://github.com/pimcore/pimcore/security/advisories/GHSA-2v88-qq7x-xq5f
- https://huntr.dev/bounties/e4cb9cd8-89cf-427c-8d2e-37ca40099bf2/
