Threats / Citrix / CVE-2023-3519
CVE-2023-3519
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Citrix NetScaler ADC and Gateway vulnerability
Citrix NetScaler ADC and NetScaler Gateway contain an unauthenticated code injection vulnerability enabling remote code execution. The flaw has been exploited in the wild and leveraged in ransomware campaigns.
Verdict
Today item, not a backlog item.
Critical unauthenticated remote code execution in widely deployed network appliances. High EPSS score and active exploitation indicate immediate threat to internet-facing infrastructure. Prioritize patching across all affected instances.
CISA KEV Yes · 2023-07-193Ransomware use Flagged3EPSS 0.99343 (verify live)4Exploit Weaponized · public PoC5
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
129 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-07-19), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.99343 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Citrix, NetScaler ADC and NetScaler Gateway. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-94 Code Injection — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious input that exploits the code injection flaw to execute arbitrary commands on the target NetScaler appliance without authentication.
Business
Attackers gain immediate code execution on critical network infrastructure, bypassing all access controls and enabling lateral movement into protected networks.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I establish persistent access and deploy ransomware payloads across the compromised network infrastructure.
Business
Ransomware operators encrypt critical systems and demand payment, disrupting business operations and threatening data confidentiality.
3
Lateral reach — past segmentation narrative 3
Attacker
I exfiltrate sensitive data transiting through the compromised gateway appliance.
Business
Customer data, intellectual property, and confidential communications are stolen, creating regulatory liability and reputational damage.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05