CVE-2026-20026
📋 TL;DR
This vulnerability in Cisco products allows unauthenticated remote attackers to cause Snort 3 Detection Engine to leak sensitive information or restart, interrupting packet inspection. It affects systems using Snort 3 for DCE/RPC traffic inspection. The issue stems from buffer handling errors in DCE/RPC request processing.
💻 Affected Systems
- Cisco products using Snort 3 Detection Engine
⚠️ 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
Continuous DoS attacks causing repeated Snort 3 restarts, leading to extended periods of no packet inspection and potential information leakage.
Likely Case
Intermittent Snort 3 restarts causing temporary packet inspection interruptions and potential information disclosure.
If Mitigated
Minimal impact with proper network segmentation and monitoring detecting anomalous DCE/RPC traffic patterns.
🎯 Exploit Status
Exploitation requires sending large volumes of DCE/RPC requests through established connections inspected by Snort 3. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Snort 3 version 3.1.58.0 or later
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-dcerpc-vulns-J9HNF4tH
Restart Required: Yes
Instructions:
1. Download Snort 3 version 3.1.58.0 or later from Cisco. 2. Stop Snort 3 service. 3. Install updated version. 4. Restart Snort 3 service. 5. Verify version and functionality.
🔧 Temporary Workarounds
Disable DCE/RPC inspection
allTemporarily disable DCE/RPC traffic inspection in Snort 3 if not required
# Edit Snort 3 configuration to remove/disable DCE/RPC preprocessor rules
Rate limit DCE/RPC traffic
allImplement network-level rate limiting for DCE/RPC traffic to prevent large request volumes
# Use firewall or network device to rate limit DCE/RPC connections
🧯 If You Can't Patch
- Implement strict network segmentation to limit DCE/RPC traffic to trusted sources only
- Deploy additional monitoring and alerting for anomalous DCE/RPC traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check Snort 3 version: snort -V | grep 'Version' and compare to 3.1.58.0Check Version:
snort -V | grep 'Version'Verify Fix Applied:
Verify Snort 3 version is 3.1.58.0 or later: snort -V | grep 'Version'📡 Detection & Monitoring
Log Indicators:
- Snort 3 process restarts
- Buffer handling errors in Snort logs
- Unusual DCE/RPC traffic volume
Network Indicators:
- High volume of DCE/RPC requests from single sources
- Abnormal DCE/RPC packet patterns
SIEM Query:
source="snort.log" AND ("restart" OR "buffer error" OR "DCE/RPC" AND volume>threshold)