Buffer overflow in Citrix Netscaler Adc

CVE-2023-4966

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.

Vulnerability class: Buffer Overflow

EPSS: 0.943 (100.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L.

Affected products

Weakness classification (CWE)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: .

Required action: Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.

Known ransomware campaign use: yes.

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-4966?
CVE-2023-4966 is a critical-severity vulnerability in Citrix Netscaler Adc, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.4/10. Published 2023-10-10.
How severe is CVE-2023-4966?
Critical severity. CVSS v3 base score is 9.4 out of 10.
Is CVE-2023-4966 known to be exploited?
Yes. CVE-2023-4966 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-10-18), indicating it is being actively exploited. 57 public proof-of-concept repositories are indexed.