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- Security Affairs
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- Zero-days, Malware & exploits
Citrix confirmed two critical NetScaler zero-days were exploited before patches were available, with attackers able to remotely execute code. Citrix confirmed that two critical zero-day vulnerabilities in NetScaler ADC and NetScaler Gateway were exploited before the company released patches. The flaws allow remote code execution, meaning attackers can potentially take control of affected appliances. The…
If you run the affected product
- Find every instance – especially the ones reachable from the internet.
- Apply the vendor's patch or mitigation now: exploited flaws are fixed in days, not at the next patch cycle.
- Then check for signs it was used before you patched: web shells, new accounts, unusual outbound traffic.
More helpCISA's Known Exploited Vulnerabilities catalogue (opens in a new tab)
Defender’s notebook
The attacker technique behind this story, in MITRE’s terms – and what to check in your own estate.
Exploit Public-Facing Application
Initial AccessWhat a defender checks
- Find every internet-facing instance of the affected product.
- Patch, or apply the vendor's mitigation now – CISA's KEV list gives a deadline.
- Look for signs it was exploited before you patched: web shells, new accounts, odd outbound traffic.
Build the skillBlue Team Analyst · Vulnerability Management
External Remote Services
Persistence, Initial AccessWhat a defender checks
- List every VPN, remote desktop and remote-access gateway you expose.
- Require MFA on all of them, and keep them patched.
- Alert on sign-ins from new countries, networks or devices.
Build the skillBlue Team Engineer · Network Security Engineering
© 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation.
MyCyberWay training
Blue Team Analyst · Vulnerability Management
You can't patch everything at once. Learn what to fix first.
In our Blue Team Analyst programme you run a vulnerability scan, prioritise the output with CVSS, EPSS and asset criticality, and track remediation to closure with the teams who own the fix.
- Read scanner output properly
- Prioritise with CVSS, EPSS and asset criticality
- Track remediation to closure
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