CVE-2025-6543
Confirmed PUBLISHEDMemory overflow vulnerability leading to unintended control flow and Denial of Service
1 day faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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
- CVE Published
- Jun 25, 2025
- Exploitation Reported
- Jun 01, 2026
- CVSS
- 9.2 Critical
- EPSS
- 9.8%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| NetScaler |
ADC
|
14.1 to < 47.46 |
Affected |
| NetScaler |
ADC
|
13.1 to < 59.19 |
Affected |
| NetScaler |
ADC
|
13.1 FIPS and NDcPP to < 37.236 |
Affected |
| NetScaler |
Gateway
|
14.1 to < 47.46 |
Affected |
| NetScaler |
Gateway
|
13.1 to < 59.19 |
Affected |
| NetScaler |
Gateway
|
13.1 FIPS and NDcPP to < 37.236 |
Affected |
CVE References
- support.citrix.com/support-home/kbsearch/article support.citrix.com · CVE Record https://support.citrix.com/support-home/kbsearch/article?articleNumbe...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 10:36 UTC |
| CISA | 2026-06-02 14:07 UTC |
| Daily CyberSecurity | 2026-06-06 02:20 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitation Status
Exploited in the wild
Recorded 2026-06-01 10:36:14 UTC · CVE
Weaknesses (CWE)
-
Improper Restriction of Operations within the Bounds of a Memory Buffer
Recent Mentions
Daily CyberSecurity · Jun 09, 2026
Multiple Memory Exploits Resolved in Major Version 2.4.68 Maintenance Cycle The development group managing the global web server The post Emergency Patch Release Secures Apache HTTP Server Deployments Against Remote Attacks appeared first on Daily CyberSecurity. Related posts: Urgent Citrix NetScaler Alert: Critical Memory Overflow Flaw (CVE-2025-6543, CVSS 9.2) Actively Exploited on 2,100+ Unpatched Appliances Apache bRPC Flaw (CVE-2025-54472) Allows Remote Denial-of-Service Attack Critical WordPress Plugin Flaw (CVE-2025-7384, CVSS 9.8) Exposes 70,000+ Sites to RCE and Data Loss
Daily CyberSecurity · Jun 08, 2026
Security Alert: Urgent Action Required for Progress Sitefinity Progress Sitefinity has issued a high-priority alert regarding several major The post Critical Sitefinity Vulnerabilities: CVSS 10.0 Security Alert appeared first on Daily CyberSecurity. Related posts: High-Severity Flaw in HashiCorp Nomad (CVE-2025-4922) Allows Privilege Escalation TeamViewer Remote Management Bug (CVE-2025-36537) Enables Privilege Escalation Urgent Citrix NetScaler Alert: Critical Memory Overflow Flaw (CVE-2025-6543, CVSS 9.2) Actively Exploited on 2,100+ Unpatched Appliances
Daily CyberSecurity · Jun 06, 2026
Severe Infrastructure Exposure Discovered The Cybersecurity and Infrastructure Security Agency (CISA) recently added a new threat to its The post CISA Warns of Actively Exploited SolarWinds Serv-U Flaw appeared first on Daily CyberSecurity. Related posts: The ‘Must-Patch’ List: CISA Adds Actively Exploited SolarWinds, Ivanti, and Omnissa Flaws to KEV Urgent Citrix NetScaler Alert: Critical Memory Overflow Flaw (CVE-2025-6543, CVSS 9.2) Actively Exploited on 2,100+ Unpatched Appliances CISA Alert: Actively Exploited Zero-Days in CrushFTP, Chrome, and SysAid Added to KEV Catalog
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
02:20 UTC about 1 month ago02:20 UTC · about 1 month ago
KEV confirmed by Daily CyberSecurity
Exploitation attested by an external source
-
14:07 UTC about 2 months ago14:07 UTC · about 2 months ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
10:36 UTC about 2 months ago10:36 UTC · about 2 months ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
12:49 UTC about 1 year ago12:49 UTC · about 1 year ago
CVE published
Vulnerability disclosed publicly
-
18:08 UTC about 1 year ago18:08 UTC · about 1 year ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2025-6543
{
"cve_id": "CVE-2025-6543",
"title": "Memory overflow vulnerability leading to unintended control flow and Denial o...",
"affected_vendor": "NetScaler",
"affected_product": "ADC, Gateway",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.2,
"epss_score": 0.09756,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}