high Known exploitedREV. 01
CVE-2023-6549Citrix NetScaler — a buffer that reads past its end
Citrix NetScaler (ADC and Gateway) mishandles a memory buffer, so a request with no credentials behind it reads out of bounds or takes the appliance down. Only devices set up as a gateway or authentication server are exposed.
Read the risk
THE VITAL STATS- CVSS score
- 7.5/ 10 CVSS v3.1
- EPSS probability
- 58% Likelihood of exploitation
- Attack complexity
- Low Conditions needed to exploit
- Known exploited
- Yes — CISA KEV
- CVE published
- 2024-01-17
- Added to KEV
- 2024-01-17
- Exploit published
- Not recorded
- Confidence
- medium
- Kill chain
- impact
- MITRE ATT&CK
- T1499
- Severity
- high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attacker needsThe appliance must be configured as a gateway or authentication virtual server.
Behind the card
3 REFERENCES- 01CVE recordNVD recordnvd.nist.gov
- 02CISACISA Known Exploited Vulnerabilities catalogcisa.gov
- 03Vendor advisorysupport.citrix.comsupport.citrix.com
Field-level provenanceTRACE THE SOURCES +
Which source supports each field, when it was retrieved, and who extracted it.
| Fields | Source | Retrieved | Extractor | Confidence |
|---|---|---|---|---|
| cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_at | nvd.nist.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| exploitation.known_exploited, exploitation.kev_added | cisa.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| epss | api.first.org | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisites | nvd.nist.gov | 2026-09-24 | claude-code | high |
Printing history
THE RECORD- r1Initial base card
First printing. This card has not been reprinted since publication.