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CVE-2023-4966 · CVE record: PUBLISHED

Unauthenticated sensitive information disclosure

Citrix NetScaler ADC, Citrix NetScaler Gateway

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.

Exploitation evidence

Known exploited · CISA KEV listed

Added 2023-10-18. Ransomware campaign use: Known.

CISA required action: 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.

CISA due date: 2023-11-08. This is the catalog’s deadline, not an assessment of your organization’s exposure.

KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗

Reported products and versions

Citrix / NetScaler ADC

Default status: unaffected

affected: 14.1 to < 8.50 (patch)
affected: 13.1 to < 49.15 (patch)
affected: 13.0 to < 92.19 (patch)
affected: 13.1-FIPS to < 37.164 (patch)
affected: 12.1-FIPS to < 55.300 (patch)
affected: 12.1-NDcPP to < 55.300 (patch)

Citrix / NetScaler Gateway

Default status: unaffected

affected: 14.1 to < 8.50 (patch)
affected: 13.1 to < 49.15 (patch)
affected: 13.0 to < 92.19 (patch)

Fixes and workarounds

No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.

Sources and related reporting

CVE Program record ↗ · Download tracked evidence as JSON

Observed change timeline

History begins when Egret first downloads each source. It is not the complete upstream CVE history.

12 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-12",
  "epss": 0.99999,
  "percentile": 0.99997
}

10 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.99999,
  "percentile": 0.99997
}

09 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.99999,
  "percentile": 0.99997
}

08 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.99999,
  "percentile": 0.99997
}

07 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.99999,
  "percentile": 0.99997
}

06 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.99999,
  "percentile": 0.99997
}

06 Nov 2026, 06:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.99999,
  "percentile": 0.99997
}

04 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.99999,
  "percentile": 0.99997
}

04 Nov 2026, 18:20 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

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  "containers": {
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            "url": "https://support.citrix.com/article/CTX579459"
          },
          {
            "tags": [
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            "url": "http://packetstormsecurity.com/files/175323/Citrix-Bleed-Session-Token-Leakage-Proof-Of-Concept.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
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              "content": {
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                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2023-10-10T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2023-10-18",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4966"
              },
              "type": "kev"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-31T03:55:28.627Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4966"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2023-10-18T00:00:00.000Z",
            "value": "CVE-2023-4966 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "NetScaler ADC",
          "vendor": "Citrix",
          "versions": [
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            {
              "lessThan": "49.15",
              "status": "affected",
              "version": "13.1",
              "versionType": "patch"
            },
            {
              "lessThan": "92.19",
              "status": "affected",
              "version": "13.0",
              "versionType": "patch"
            },
            {
              "lessThan": "37.164",
              "status": "affected",
              "version": "13.1-FIPS",
              "versionType": "patch"
            },
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              "status": "affected",
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              "status": "affected",
              "version": "12.1-NDcPP",
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            {
              "lessThan": "49.15",
              "status": "affected",
              "version": "13.1",
              "versionType": "patch"
            },
            {
              "lessThan": "92.19",
              "status": "affected",
              "version": "13.0",
              "versionType": "patch"
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        }
      ],
      "datePublic": "2023-10-10T12:33:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "base64": false,
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            }
          ],
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 9.4,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L",
            "version": "3.1"
          },
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      ],
      "problemTypes": [
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              "cweId": "CWE-119",
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              "lang": "en",
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      ],
      "providerMetadata": {
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        "orgId": "e437aed5-38e0-4fa3-a98b-cb73e7acaec6",
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      },
      "references": [
        {
          "url": "https://support.citrix.com/article/CTX579459"
        },
        {
          "url": "http://packetstormsecurity.com/files/175323/Citrix-Bleed-Session-Token-Leakage-Proof-Of-Concept.html"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Unauthenticated sensitive information disclosure",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "e437aed5-38e0-4fa3-a98b-cb73e7acaec6",
    "assignerShortName": "Citrix",
    "cveId": "CVE-2023-4966",
    "datePublished": "2023-10-10T13:12:17.644Z",
    "dateReserved": "2023-09-14T15:51:21.569Z",
    "dateUpdated": "2026-07-31T03:55:28.627Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

03 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.99999,
  "percentile": 0.99997
}

03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.99999,
  "percentile": 0.99997
}

03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2023-4966",
  "cwes": [
    "CWE-119"
  ],
  "dateAdded": "2023-10-18",
  "dueDate": "2023-11-08",
  "forensicTriage": "No",
  "knownRansomwareCampaignUse": "Known",
  "notes": "https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/, https://support.citrix.com/article/CTX579459/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20234966-and-cve20234967 ;  https://nvd.nist.gov/vuln/detail/CVE-2023-4966",
  "product": "NetScaler ADC and NetScaler Gateway",
  "requiredAction": "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.",
  "shortDescription": "Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.",
  "vendorProject": "Citrix",
  "vulnerabilityName": "Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability"
}

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