CVE-2025-6543

Name: CVE-2025-6543
Creator: NVD / NIST
Published: 2025-06-25T13:15:27.293+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.2/10Actively ExploitedEPSS 9.76%

Last modified Jun 17, 2026

CVE-2025-6543 is a critical-severity vulnerability rated 9.2/10 on the CVSS scale. 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. CISA has confirmed active exploitation in the wild. EPSS estimates a 9.76% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

9.2/10

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

9.76%

94.9th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Jul 21, 2025.

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Citrix	Netscaler Application Delivery Controller	>= 13.1, < 13.1-37.236
Citrix	Netscaler Application Delivery Controller	>= 13.1, < 13.1-59.19
Citrix	Netscaler Application Delivery Controller	>= 14.1, < 14.1-47.46
Citrix	Netscaler Gateway	>= 13.1, < 13.1-59.19
Citrix	Netscaler Gateway	>= 14.1, < 14.1-47.46

References

https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX694788Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-6543US Government Resource

Timeline

Published: Jun 25, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-6543?

How severe is CVE-2025-6543?

CVE-2025-6543 has a CVSS score of 9.2/10 (CRITICAL severity). The EPSS model estimates a 9.76% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2025-6543?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-6543?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST