Buffer overflow in Citrix Netscaler_application_delivery_controller
CVE-2025-6543
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
Vulnerability class: Buffer Overflow
EPSS: 0.098 (95.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Citrix Netscaler_application_delivery_controller
- Citrix Netscaler_gateway
- Netscaler Adc — versions 14.1, 13.1, 13.1 FIPS and NDcPP
- Netscaler Gateway — versions 14.1, 13.1, 13.1 FIPS and NDcPP
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- secure@citrix.com (Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2025-6543?
- CVE-2025-6543 is a critical-severity vulnerability in Citrix Netscaler_application_delivery_controller, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2025-06-25.
- How severe is CVE-2025-6543?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2025-6543 known to be exploited?
- Yes. CVE-2025-6543 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-06-30), indicating it is being actively exploited. 20 public proof-of-concept repositories are indexed.