CISA Known Exploited Vulnerability
This vulnerability is actively exploited in the wild and listed in the CISA Known Exploited Vulnerabilities catalog.
Remediation Deadline: Nov 8, 2023
Description
Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.
EPSS — Exploit Probability
Higher than 100.0% of all CVEs
Required Action
https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/, https://support.citrix.com/article/CTX579459/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20234966-and-cve20234967 ; https://nvd.nist.gov/vuln/detail/CVE-2023-4966
Related Articles (4)
ThreatsDay Bulletin: FortiGate RaaS, Citrix Exploits, MCP Abuse, LiveChat Phish & More
ThreatsDay roundup covering stealthy attacks, phishing trends, exploit chains, and rising security risks across the threat landscape.
Mar 19, 2026
Citrix Urges Patching Critical NetScaler Flaw Allowing Unauthenticated Data Leaks
Citrix fixes CVE-2026-3055 memory flaw in NetScaler, enabling data leaks in SAML setups, raising risk of imminent exploitation.
Mar 24, 2026
Citrix urges admins to patch NetScaler flaws as soon as possible
Citrix has patched two NetScaler ADC and NetScaler Gateway vulnerabilities, one of which is very similar to the CitrixBleed and CitrixBleed2 flaws exploited in zero-day attacks in recent years.
Mar 25, 2026
Citrix NetScaler Under Active Recon for CVE-2026-3055 (CVSS 9.3) Memory Overread Bug
CVE-2026-3055 targets Citrix NetScaler with active reconnaissance, risking data leaks on SAML IDP setups.
Mar 28, 2026
Risk Assessment
CRITICALDetails
- Severity
- High
- EPSS
- 94.3%
- CISA KEV
- Yes
- Ransomware
- Known
- Articles
- 4
Timeline
Published
Oct 18, 2023
Added to KEV
Oct 18, 2023
Remediation Due
Nov 8, 2023