1. Cleus
  2. Zero-days
  3. CVE-2023-3519
Exploited in the wildUsed by ransomwareVPNs, firewalls & gatewaysWork IT

CVE-2023-3519 Citrix NetScaler ADC and NetScaler Gateway: command or code injection

In plain words: The program treats text it receives as instructions instead of plain data. The attacker can run commands on the machine — often the whole device is taken over.

Confirmed exploited by CISA on · US federal patch deadline Aug 9, 2023

What to do

  1. Install Citrix's security update for NetScaler ADC and NetScaler Gateway. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Patch edge devices first — attackers often start scanning for them within hours of a fix.
  3. Never expose the device's admin page to the internet.
  4. After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.

Read Citrix's advisory ↗

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.

The details

Official name
Citrix NetScaler ADC and NetScaler Gateway Code Injection Vulnerability
Product
Citrix NetScaler ADC and NetScaler Gateway
CISA description
Citrix NetScaler ADC and NetScaler Gateway contains a code injection vulnerability that allows for unauthenticated remote code execution.
Type of flaw
Command or code injection (CWE-94)
Confirmed exploited
Jul 19, 2023 — known to be used in ransomware attacks
US federal patch deadline
Aug 9, 2023

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Answering about CVE-2023-3519 ·

Questions about CVE-2023-3519

Is CVE-2023-3519 being exploited?

Yes. CISA added CVE-2023-3519 to its Known Exploited Vulnerabilities catalog on Jul 19, 2023, which means there is reliable evidence of real-world attacks, including by ransomware groups.

How do I fix CVE-2023-3519?

Install Citrix's security update for NetScaler ADC and NetScaler Gateway. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.

Am I affected by CVE-2023-3519?

Only if you use Citrix NetScaler ADC and NetScaler Gateway. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

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