CVE-2019-12991
HIGHCitrix SD-WAN 10.2.x before 10.2.3 and NetScaler SD-WAN 10.0.x before 10.0.8 have Improper Input Validation (issue 5 of 6).
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
Citrix SD-WAN 10.2.x before 10.2.3 and NetScaler SD-WAN 10.0.x before 10.0.8 have Improper Input Validation (issue 5 of 6).
Affected Products
netscaler sd-wancitrixsd-wancitrixResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Citrix SD-WAN Appliance 10.2.2 - Authentication Bypass / Remote Command Execution
by Chris Lyne · Jul 12, 2019
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every citrix netscaler sd-wan deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the citrix netscaler sd-wan security patch or hotfix for CVE-2019-12991 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2019-12991 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2019-12991. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2019-12991 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2019-12991 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.