Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:LSummary
CVE-2023-4966 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Citrix Netscaler Application Delivery Controller. Its CVSS base score is 9.4 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Process Injection (T1055); ranked in the top 0.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2023-4966 is a sensitive information disclosure vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway appliances when configured as a Gateway (including VPN virtual server, ICA Proxy, CVPN, or RDP Proxy) or as an AAA virtual server. The flaw, tracked under CWE-119, carries a CVSS 3.1 score of 9.4 and permits exposure of sensitive session data without requiring authentication or user interaction.
Unauthenticated remote attackers can exploit the issue over the network to leak session tokens and other sensitive information, enabling session hijacking and subsequent unauthorized access with impacts to confidentiality, integrity, and availability. Public proof-of-concept code has been released that demonstrates token leakage against vulnerable instances.
Citrix advisory CTX579459 details the affected versions and provides remediation guidance, while CISA has added the CVE to its Known Exploited Vulnerabilities catalog, confirming in-the-wild exploitation. The associated EPSS score has reached a peak of 0.9717 with a current value of 0.9435, indicating sustained and substantial exploitation interest following disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-54802
Vulnerability Data
Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.
- CWE(s)
- KEV Date Added
- 18 October 2023
Related Threats
Threat-Actor AttributionAI
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V17.3.2
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.
Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.
Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.
Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices (bounds checking, safe APIs, reviews) directly prevent this class of flaw.
Vulnerability scanning and code analysis directly surface buffer-boundary flaws.
Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.
Developer training on secure coding reduces introduction of memory-buffer errors.
Patching replaces vulnerable code containing buffer-boundary defects.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.
Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.
Application security requirements can specify memory-safety rules, but do not prescribe implementation details.
Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.
Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.