Exploited CVEs / Citrix / CVE-2023-6549
CVE-2023-6549
Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2024-02-07 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Citrix Security Bulletins, linked below.
Actively exploited Citrix NetScaler ADC and NetScaler Gateway vulnerability, High severity, CVSS 7.5. Added to the CISA KEV catalog 2024-01-17.
Risk summary
Updated July 26, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2023-6549
Citrix NetScaler ADC and Gateway appliances configured as a Gateway or AAA virtual server can be knocked over remotely through this buffer overflow, a denial of service against the very appliance providing your remote access. Exploited alongside a sibling code injection flaw and KEV-listed in January 2024, it continues NetScaler's run as one of the most attacked appliance families. The 58 percent EPSS shows sustained attacker interest.
Do this: Update NetScaler firmware on all Gateway and AAA-configured appliances, prioritizing the ones your remote workforce depends on.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2023-6549
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2023-6549
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2024-02-07 (past due).
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Official fix for CVE-2023-6549
The authoritative fix and affected-version list are published by the vendor. Find the NetScaler ADC and NetScaler Gateway advisory on Citrix Security Bulletins.
Common questions about CVE-2023-6549
Is CVE-2023-6549 actively exploited?
Yes. CVE-2023-6549 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2024-01-17, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 58%.
What is the CISA deadline and required action for CVE-2023-6549?
CISA set the federal (BOD 22-01) remediation due date at 2024-02-07, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
What fixes CVE-2023-6549?
The authoritative fix is in the vendor advisory: see Citrix Security Bulletins for the patched NetScaler ADC and NetScaler Gateway versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2023-6549?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2023-6549's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
