CVE-2026-22904
📋 TL;DR
This critical vulnerability allows unauthenticated remote attackers to trigger a stack buffer overflow by sending oversized cookie values. Successful exploitation can cause denial-of-service or potentially remote code execution. Any system running affected software that processes HTTP cookies is vulnerable.
💻 Affected Systems
- Software with vulnerable cookie parsing implementation
⚠️ 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
Remote code execution with full system compromise, allowing attacker to execute arbitrary code with application privileges.
Likely Case
Denial-of-service causing application crashes and service disruption, with potential for limited code execution.
If Mitigated
Application crash and restart with no persistent impact if proper memory protections are enabled.
🎯 Exploit Status
The vulnerability requires sending specially crafted oversized cookie values but does not require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://certvde.com/de/advisories/VDE-2026-004
Restart Required: Yes
Instructions:
1. Monitor vendor for security patches. 2. Apply patches when available. 3. Restart affected services after patching.
🔧 Temporary Workarounds
Cookie Size Limiting
allConfigure web server or application to reject oversized cookie values
# Apache: LimitRequestFieldSize 4096
# Nginx: large_client_header_buffers 4 8k
# Application-level: Validate cookie length before processing
Web Application Firewall Rules
allBlock requests with oversized cookie headers
# WAF rule to block cookies > 4096 bytes
# Example ModSecurity: SecRule REQUEST_HEADERS:Cookie "@gt 4096" "id:1001,phase:1,deny"
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems
- Deploy intrusion detection systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Test by sending oversized cookie values (>4096 bytes) to the application and monitoring for crashes or unexpected behavior.Check Version:
Check application version against vendor advisory when availableVerify Fix Applied:
After applying mitigations, test with oversized cookies to ensure they are rejected without causing crashes.📡 Detection & Monitoring
Log Indicators:
- Application crashes or restarts
- Error logs showing buffer overflow or memory corruption
- Unusually large cookie values in access logs
Network Indicators:
- HTTP requests with cookie headers exceeding normal size (typically >4096 bytes)
- Multiple rapid requests with large cookies
SIEM Query:
source="web_logs" AND (cookie_length > 4096 OR message="*buffer overflow*" OR message="*segmentation fault*")