CVE-2023-4966Unauthenticated sensitive information disclosure
- 9.4CriticalCVSS base score
- 100.0%Exploitation in 30 daysEPSS · top 0.1% of all CVEs
- YesKnown exploitedin CISA's KEV since 18 Oct 2023
- 2Public exploitsMetasploit, Nuclei and Exploit-DB
Description
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability.
- Added
- 18 Oct 2023
- Fix due (US federal)
- 8 Nov 2023
- Used by ransomware
- Known
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.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 18 Oct 2023.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Metasploit module and a Nuclei template for it. CISA's SSVC rates its exploitation: it is being exploited.
Show the exploits2
Metasploit modules1 module
- Citrix ADC (NetScaler) Bleed Scanner (Metasploit module) (opens in a new tab)
auxiliary/scanner/http/citrix_bleed_cve_2023_4966Rank normaldisclosed 25 Oct 2023
Nuclei templates1 template
- Citrix Bleed - Leaking Session Tokens (Nuclei template) (opens in a new tab)
http/cves/2023/CVE-2023-4966.yamlSeverity high
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By Citrix
- 26 days later
· 26 days later
Published
- 8 days later
· 8 days later
Added to CISA KEV
Known exploited, also by ransomware
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CitrixCNA (assigner) | 3.1 | Critical9.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 100.0% · top 0.1% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.4.
Affected products
- affected 14.1 – < 8.50
- affected 13.1 – < 49.15
- affected 13.0 – < 92.19
- affected 13.1-FIPS – < 37.164
- affected 12.1-FIPS – < 55.300
- affected 12.1-NDcPP – < 55.300
- affected 14.1 – < 8.50
- affected 13.1 – < 49.15
- affected 13.0 – < 92.19
References
References3
- https://support.citrix.com/article/CTX579459 (opens in a new tab)x_transferred
- http://packetstormsecurity.com/files/175323/Citrix-Bleed-Session-Token-Leakage-Proof-Of-Concept.html (opens in a new tab)x_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4966 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-54802 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-4966)Record last updated .