{"id":56436,"date":"2025-07-01T14:53:11","date_gmt":"2025-07-01T14:53:11","guid":{"rendered":""},"modified":"2025-09-26T11:38:39","modified_gmt":"2025-09-26T17:38:39","slug":"cve-2025-6543-critical-memory-overflow-vulnerability-in-netscaler-adc-and-gateway","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-6543-critical-memory-overflow-vulnerability-in-netscaler-adc-and-gateway\/","title":{"rendered":"CVE-2025-6543: Critical Memory Overflow Vulnerability in NetScaler ADC and Gateway<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

The cybersecurity world has been rocked by a new discovery: CVE-2025-6543, a critical memory overflow vulnerability affecting NetScaler ADC and NetScaler Gateway. This vulnerability has the potential to dramatically disrupt system functionality and compromise data security. The issue particularly impacts systems configured as Gateway (VPN virtual server<\/a>, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server. As a high-priority issue, it has been assigned a Common Vulnerability Scoring System<\/a> (CVSS) score of 9.8, marking it as a severe threat to the integrity of affected systems.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-6543
\nSeverity: Critical (CVSS: 9.8)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Potential system<\/a> compromise and data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

NetScaler ADC<\/a> | All versions
\nNetScaler Gateway | All versions<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit takes advantage of a memory overflow vulnerability<\/a> within the NetScaler ADC and Gateway systems. When these systems are configured<\/a> as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server, they become susceptible to the vulnerability. An attacker can send specially crafted data packets to these servers, causing them to overflow their memory buffers<\/a>. This leads to unintended control<\/a> flow and results in a Denial of Service (DoS) condition. Furthermore, this vulnerability can potentially lead to system compromise and data<\/a> leakage.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Here\u2019s a conceptual example illustrating how the vulnerability<\/a> might be exploited:<\/p>\n

POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/octet-stream\n{ \"data\": \"A\".repeat(1000000) }<\/code><\/pre>\n
In the above example, the attacker sends a POST request to the vulnerable endpoint<\/a> with a large payload of repeated ‘A’ characters. This payload is larger than the memory buffer allocated to handle the incoming data, leading to a buffer<\/a> overflow. This can cause the system to execute unintended instructions and potentially grant unauthorized access<\/a> to the attacker.<\/p>\n
Mitigation Measures<\/strong><\/p>\n
To mitigate the risks associated with CVE-2025-6543, users are advised to immediately apply the vendor patch. If the patch is unavailable or cannot be immediately applied, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. These systems can be configured to detect and block attempts to exploit this vulnerability<\/a>. However, they should not be considered a long-term solution, and patching the software remains the most effective way to secure<\/a> your systems.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview The cybersecurity world has been rocked by a new discovery: CVE-2025-6543, a critical memory overflow vulnerability affecting NetScaler ADC and NetScaler Gateway. This vulnerability has the potential to dramatically disrupt system functionality and compromise data security. The issue particularly impacts systems configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[],"product":[],"attack_vector":[86,87],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-56436","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-buffer-overflow","attack_vector-dos"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t