Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2024-01-17
• EPSS: 58% chance of exploitation in the next 30 days (higher than 99% of CVEs)

[ Description ]Official description

Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read

CISA: Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for a denial-of-service when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 7 Feb 2024): Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulle…Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource