Security Digest · Vulnerability record
CVE-2023-4967: Denial of service
Denial of Service in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA Virtual Server
CVSS 8.2 High EPSS 1.1% · p65 Act now
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.1%, percentile 65: FIRST’s model estimates a 1.1% chance of exploitation activity in the next 30 days, higher than 65% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Act now. Citrix Bleed: NetScaler Gateway Leaks Session Tokens — If a NetScaler configured as a Gateway or AAA server is still on a vulnerable build, assume it is being probed and patch, kill every session, and hunt; patching alone does not evict an attacker holding a stolen session.
What it is
Denial of Service in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA Virtual Server
Weakness type: CWE-119.
Product: Cloud Software Group NetScaler ADC · Assigned by: Citrix · Published: 2023-10-27
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Cloud Software Group | NetScaler ADC | 14.1 < 8.50, 13.1 < 49.15, 13.0 < 92.19, 13.1-FIPS < 37.164, 12.1-FIPS < 55.300, 12.1-NDcPP < 55.300 |
| Cloud Software Group | NetScaler Gateway | 14.1 < 8.50, 13.1 < 49.15, 13.0 < 92.19 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| Citrix | 3.1 | 8.2 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 1.09% probability of exploitation activity in the next 30 days; percentile 65.
Timeline
- — erroneo.us brief: Citrix Bleed: NetScaler Gateway Leaks Session Tokens
- — CVE record published by Citrix
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2023-4967 cve.org
- NVD entry CVE-2023-4967 nvd.nist.gov
Other references from the CVE record and advisory
- support.citrix.com support.citrix.com