CVE-2025-25234
📋 TL;DR
Omnissa UAG contains a CORS bypass vulnerability that allows attackers with network access to circumvent administrator-configured CORS restrictions. This could enable unauthorized access to sensitive networks and resources. Organizations using vulnerable Omnissa UAG deployments are affected.
💻 Affected Systems
- Omnissa Unified Access Gateway (UAG)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could bypass CORS restrictions to access sensitive internal networks, potentially leading to data exfiltration, lateral movement, or compromise of protected resources.
Likely Case
Attackers with network access could bypass CORS policies to access restricted APIs or services, potentially exposing sensitive data or functionality.
If Mitigated
With proper network segmentation and access controls, the impact is limited to the specific UAG instance and its directly accessible resources.
🎯 Exploit Status
Exploitation requires network access but no authentication; attacker needs to craft malicious requests to bypass CORS restrictions
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific patched versions
Vendor Advisory: https://www.omnissa.com/omnissa-security-response/
Restart Required: Yes
Instructions:
1. Review vendor advisory at provided URL. 2. Download and apply the security patch for your UAG version. 3. Restart UAG services as required. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to UAG instances to only trusted sources
CORS Policy Review
allReview and tighten CORS policies to minimize allowed origins and methods
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach UAG instances
- Deploy web application firewall (WAF) rules to detect and block CORS bypass attempts
🔍 How to Verify
Check if Vulnerable:
Check UAG version against vendor advisory; test CORS policies with controlled requestsCheck Version:
Check UAG administration interface or documentation for version commandVerify Fix Applied:
Verify UAG version is updated to patched version; test that CORS restrictions are properly enforced📡 Detection & Monitoring
Log Indicators:
- Unusual CORS-related request patterns
- Requests from unexpected origins bypassing CORS
Network Indicators:
- HTTP requests with crafted Origin headers attempting to bypass CORS
- Unusual cross-origin requests to UAG
SIEM Query:
Search for HTTP requests to UAG with Origin headers that don't match allowed patterns