CVE-2023-6549Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated…
- 8.2HighCVSS base score
- 57.6%Exploitation in 30 daysEPSS · top 0.9% of all CVEs
- YesKnown exploitedin CISA's KEV since 17 Jan 2024
- 1Public exploitsMetasploit, Nuclei and Exploit-DB
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
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
- 17 Jan 2024
- Fix due (US federal)
- 7 Feb 2024
- Used by ransomware
- Not known
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 17 Jan 2024.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Nuclei template for it. CISA's SSVC rates its exploitation: it is being exploited.
Show the exploits1
Nuclei templates1 template
- Citrix Netscaler ADC & Gateway - Out-Of-Bounds Memory Read (Nuclei template) (opens in a new tab)
http/cves/2023/CVE-2023-6549.yamlSeverity critical
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
- 42 days later
· 42 days later
Published
Added to CISA KEV
Known exploited in the wild
- 21 months later
· 21 months 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 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 57.6% · top 0.9% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Affected products
Cloud Software Group · NetScaler ADC
- affected 14.1 – < 12.35
- affected 13.1 – < 51.15
- affected 13.0 – < 92.21
- affected 13.1-FIPS – < 37.176
- affected 12.1-FIPS – < 55.302
- affected 12.1-NDcPP – < 55.302
References
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-2023-58779 (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-2023-6549)Record last updated .