How severe is CVE-2025-6543?

CVE-2025-6543 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-6543 being actively exploited?

Yes. CVE-2025-6543 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-06-30, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2025-6543?

CVE-2025-6543 primarily affects Citrix Netscaler Application Delivery Controller. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-6543?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2025-6543 have an EU (EUVD) identifier?

Yes. CVE-2025-6543 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19085. It is also flagged as exploited in the EUVD (since 2025-06-30).

When was CVE-2025-6543 published?

CVE-2025-6543 was published on 2025-06-25 and last updated on 2026-06-17.

CVE-2025-6543

CVE-2025-6543 is a critical-severity vulnerability in Citrix Netscaler Application Delivery Controller with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2025-06-30). The underlying weakness is classified as CWE-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.2
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2025-06-30)
EU (EUVD) id: EUVD-2025-19085
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2025-06-30)
Weakness: CWE-119
Affected product: Citrix Netscaler Application Delivery Controller
Published: 2025-06-25
Last modified: 2026-06-17

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

Frequently asked questions

What is 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
How severe is CVE-2025-6543?: CVE-2025-6543 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-6543 being actively exploited?: Yes. CVE-2025-6543 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-06-30, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2025-6543?: CVE-2025-6543 primarily affects Citrix Netscaler Application Delivery Controller. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-6543?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2025-6543 have an EU (EUVD) identifier?: Yes. CVE-2025-6543 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19085. It is also flagged as exploited in the EUVD (since 2025-06-30).
When was CVE-2025-6543 published?: CVE-2025-6543 was published on 2025-06-25 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*
cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*

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