CVE-2023-6549
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
Citrix NetScaler ADC and NetScaler Gateway
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
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 17 January 2024. US federal agencies were required to remediate it by 7 February 2024.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 57.6%, which is higher than 99.1% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Frequently asked questions
Is CVE-2023-6549 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2023-6549.
What does CVE-2023-6549 affect?
CVE-2023-6549 affects Citrix NetScaler ADC and NetScaler Gateway. 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
How severe is CVE-2023-6549?
CVE-2023-6549 is rated HIGH with a CVSS base score of 8.2. EPSS puts the probability of exploitation in the next 30 days at 57.6%, higher than 99.1% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 7 February 2024.
How should organisations respond to CVE-2023-6549?
Apply the vendor patch for Citrix NetScaler ADC and NetScaler Gateway as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.