CVE-2023-6549

CRITICALNVD 8.29.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2024-01-17), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.2 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • 3,432 internet-exposed hosts are running an affected version right now
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 58%CVSS: 8.2Exploit: cisa kev · ssvc active · epss top5pct · epss high · public exploitExposed: 3,432

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

Live · internet exposure

3,432 internet-exposed hosts are running an affected version of CVE-2023-6549 right now.

across 29 countries (Germany, Australia, United Kingdom, United States, Bulgaria)top: netscaler_gateway
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
8.2
EG Score
9.0(high)
EG Risk
96(Attend)
EG Risk 96/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
58%
EPSS %ILE
99%
KEV
⚠ Exploited

Published

January 17, 2024

Last Modified

February 26, 2026

Advisory Details (2)

Auto-updated Jun 3, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-6549
generic

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https://support.citrix.com/article/CTX584986/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20236548-and-cve20236549

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 58× in last 7d / 236× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 854 total refreshes for this CVE.

  1. 2026-09-19 04:24 UTCGHSA enrichment
  2. 2026-09-19 00:23 UTCGHSA enrichment
  3. 2026-09-18 20:22 UTCEG score recompute
  4. 2026-09-18 20:22 UTCGHSA enrichment
  5. 2026-09-18 19:26 UTCEPSS rescore
  6. 2026-09-18 19:20 UTCCISA KEV update
  7. 2026-09-18 16:21 UTCGHSA enrichment
  8. 2026-09-18 14:15 UTCCISA KEV update
  9. 2026-09-18 12:20 UTCGHSA enrichment
  10. 2026-09-18 08:18 UTCGHSA enrichment
  11. 2026-09-18 04:17 UTCGHSA enrichment
  12. 2026-09-18 00:16 UTCGHSA enrichment
  13. 2026-09-17 20:15 UTCEG score recompute
  14. 2026-09-17 20:15 UTCGHSA enrichment
  15. 2026-09-17 16:14 UTCGHSA enrichment
  16. 2026-09-17 12:13 UTCGHSA enrichment
  17. 2026-09-17 08:11 UTCGHSA enrichment
  18. 2026-09-17 04:10 UTCGHSA enrichment
  19. 2026-09-17 00:09 UTCGHSA enrichment
  20. 2026-09-16 20:07 UTCGHSA enrichment
  21. 2026-09-16 16:05 UTCEG score recompute
  22. 2026-09-16 16:05 UTCGHSA enrichment
  23. 2026-09-16 14:10 UTCCISA KEV update
  24. 2026-09-16 14:06 UTCEPSS rescore
  25. 2026-09-16 12:04 UTCGHSA enrichment
Show 75 more
  1. 2026-09-16 08:02 UTCEG score recompute
  2. 2026-09-16 08:02 UTCGHSA enrichment
  3. 2026-09-16 05:11 UTCEPSS rescore
  4. 2026-09-16 05:11 UTCEPSS rescore
  5. 2026-09-16 03:57 UTCGHSA enrichment
  6. 2026-09-15 23:56 UTCGHSA enrichment
  7. 2026-09-15 19:54 UTCGHSA enrichment
  8. 2026-09-15 15:52 UTCGHSA enrichment
  9. 2026-09-15 11:51 UTCGHSA enrichment
  10. 2026-09-15 07:50 UTCGHSA enrichment
  11. 2026-09-15 03:49 UTCEG score recompute
  12. 2026-09-15 03:49 UTCGHSA enrichment
  13. 2026-09-15 03:08 UTCEPSS rescore
  14. 2026-09-14 23:48 UTCGHSA enrichment
  15. 2026-09-14 19:47 UTCGHSA enrichment
  16. 2026-09-14 19:24 UTCCISA KEV update
  17. 2026-09-14 15:45 UTCGHSA enrichment
  18. 2026-09-14 11:43 UTCGHSA enrichment
  19. 2026-09-14 07:42 UTCGHSA enrichment
  20. 2026-09-14 03:41 UTCGHSA enrichment
  21. 2026-09-13 23:40 UTCGHSA enrichment
  22. 2026-09-13 19:38 UTCGHSA enrichment
  23. 2026-09-13 15:35 UTCGHSA enrichment
  24. 2026-09-13 11:33 UTCGHSA enrichment
  25. 2026-09-13 07:31 UTCGHSA enrichment
  26. 2026-09-13 03:30 UTCGHSA enrichment
  27. 2026-09-12 23:28 UTCGHSA enrichment
  28. 2026-09-12 19:26 UTCGHSA enrichment
  29. 2026-09-12 15:25 UTCEG score recompute
  30. 2026-09-12 15:25 UTCGHSA enrichment
  31. 2026-09-12 14:58 UTCEPSS rescore
  32. 2026-09-12 11:24 UTCGHSA enrichment
  33. 2026-09-12 07:23 UTCGHSA enrichment
  34. 2026-09-12 03:21 UTCGHSA enrichment
  35. 2026-09-11 23:20 UTCGHSA enrichment
  36. 2026-09-11 19:19 UTCGHSA enrichment
  37. 2026-09-11 18:49 UTCCISA KEV update
  38. 2026-09-11 15:18 UTCEG score recompute
  39. 2026-09-11 15:18 UTCGHSA enrichment
  40. 2026-09-11 14:51 UTCEPSS rescore
  41. 2026-09-11 11:16 UTCGHSA enrichment
  42. 2026-09-11 07:14 UTCGHSA enrichment
  43. 2026-09-11 03:12 UTCGHSA enrichment
  44. 2026-09-10 23:11 UTCGHSA enrichment
  45. 2026-09-10 19:28 UTCCISA KEV update
  46. 2026-09-10 19:10 UTCGHSA enrichment
  47. 2026-09-10 15:08 UTCGHSA enrichment
  48. 2026-09-10 11:06 UTCEG score recompute
  49. 2026-09-10 11:06 UTCGHSA enrichment
  50. 2026-09-10 07:01 UTCGHSA enrichment
  51. 2026-09-10 02:59 UTCGHSA enrichment
  52. 2026-09-09 22:58 UTCGHSA enrichment
  53. 2026-09-09 19:08 UTCCISA KEV update
  54. 2026-09-09 18:56 UTCGHSA enrichment
  55. 2026-09-09 14:55 UTCGHSA enrichment
  56. 2026-09-09 10:54 UTCGHSA enrichment
  57. 2026-09-09 06:52 UTCGHSA enrichment
  58. 2026-09-09 02:51 UTCGHSA enrichment
  59. 2026-09-08 22:50 UTCEG score recompute
  60. 2026-09-08 22:50 UTCGHSA enrichment
  61. 2026-09-08 21:58 UTCEPSS rescore
  62. 2026-09-08 18:54 UTCCISA KEV update
  63. 2026-09-08 18:49 UTCGHSA enrichment
  64. 2026-09-08 14:46 UTCGHSA enrichment
  65. 2026-09-08 10:43 UTCGHSA enrichment
  66. 2026-09-08 06:41 UTCGHSA enrichment
  67. 2026-09-08 02:39 UTCGHSA enrichment
  68. 2026-09-07 22:38 UTCGHSA enrichment
  69. 2026-09-07 18:36 UTCGHSA enrichment
  70. 2026-09-07 14:34 UTCGHSA enrichment
  71. 2026-09-07 10:32 UTCGHSA enrichment
  72. 2026-09-07 06:30 UTCGHSA enrichment
  73. 2026-09-07 02:26 UTCGHSA enrichment
  74. 2026-09-06 22:25 UTCGHSA enrichment
  75. 2026-09-06 18:24 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2023/CVE-2023-6549.yaml
    First seen Jan 1, 2023

    Citrix Netscaler ADC & Gateway - Out-Of-Bounds Memory Read

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2023-6549?
CVE-2023-6549 is a critical vulnerability published on January 17, 2024. 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
When was CVE-2023-6549 disclosed?
CVE-2023-6549 was first published in the National Vulnerability Database on January 17, 2024, with the most recent update on February 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-6549 actively exploited?
Yes. CISA added CVE-2023-6549 to the Known Exploited Vulnerabilities catalog on January 17, 2024, affecting Citrix NetScaler ADC and NetScaler Gateway. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2023-6549?
CVE-2023-6549 has a CVSS v3 base score of 8.2 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2023-6549?
CVE-2023-6549 affects Citrix NetScaler ADC and NetScaler Gateway. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2023-6549?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-6549, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2023-6549

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