On 2025-06-30, CISA added CVE-2025-6543 (Citrix NetScaler ADC and Gateway) to its Known Exploited Vulnerabilities (KEV) catalog [2]. The vulnerability is listed in the catalog as "Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability" [2]. CISA requires remediation in accordance with the listed vendor mitigation guidance; see the original text in the body for specific requirements [2].
Backfill: this event became public on Jun 30, 2025 and we added it on Nov 10, 2026. It is not a new event.
CISA Adds Citrix NetScaler ADC and Gateway Vulnerability CVE-2025-6543 to Known Exploited Vulnerabilities Catalog
1 min read
- Disclosed
- Jun 30, 2025
- Published
- Nov 10, 2026
- Last updated
- Nov 8, 2026
- CVSS basis
- Our assessment
- 10.4%, higher than 96% of CVEs
- Exploitation and patch status
- ExploitedKEV
- Attack vector
- Vulnerability status
- Actor type
- Motivation
On this page
30-second summary
What happened
Who is affected
Industries mainly affected: Government, Cross-industry
What to do nowOur advice
CISA requires remediation in accordance with the listed vendor mitigation guidance; see the original text in the body for specific requirements [2].
Timeline
Technical details
CISA KEV Listing Record
CISA added CVE-2025-6543 (Citrix NetScaler ADC and Gateway) to the Known Exploited Vulnerabilities () catalog on 2025-06-30 [2].
Original Technical Description
Citrix NetScaler ADC and Gateway contain a buffer overflow vulnerability leading to unintended control flow and Denial of Service. NetScaler must be configured as Gateway ( virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server. [2]
Official Required Action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. [2]
Individual Vulnerability Record
The U.S. National Vulnerability Database (NVD) provides an independent vulnerability record and description for CVE-2025-6543 [1].
References
Official / primary3
- [1]
“Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server”
- [2]
This site aggregates public information and is not security consulting advice. Test remediation steps before applying.