CVE-2026-88778

Published Sep 27, 2026

Last updated 18 days ago

CVSS high 8.8

VDI

Citrix NetScaler ADC

Citrix NetScaler Gateway

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-88778 is identified as a TCP Initial Sequence Number (ISN) prediction flaw affecting Citrix NetScaler ADC and NetScaler Gateway appliances. This vulnerability specifically impacts devices configured with TCP-based virtual servers, such as those handling HTTP, SSL, or generic TCP traffic, when the "Enhanced ISN Generation" feature is disabled. To address this issue, Citrix advises applying software updates and implementing a configuration change to enable Enhanced ISN Generation on affected appliances.

Description: Predictable exact value from previous values vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1.37.279 FIPS and NDcPP; Gateway: before 14.1-73.37 and before 13.1-64.23.
Source: 50a63c94-1ea7-4568-8c11-eb79e7c5a2b5
NVD status: Analyzed
Products: netscaler_application_delivery_controller, netscaler_gateway

Risk scores

CVSS 4.0

Type: Secondary
Base score: 8.8
Impact score: -
Exploitability score: -
Vector string: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity: HIGH

CVSS 3.1

Type: Primary
Base score: 7.5
Impact score: 3.6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Severity: HIGH

Weaknesses

50a63c94-1ea7-4568-8c11-eb79e7c5a2b5: CWE-342

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*",
            "matchCriteriaId": "6BC2D462-9ABE-4024-8E46-8D265C0B19FB",
            "versionEndExcluding": "13.1-64.23",
            "versionStartIncluding": "13.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*",
            "matchCriteriaId": "2DB314FE-3886-4ABD-A820-B8A70EBB23A6",
            "versionEndExcluding": "13.1.37.279",
            "versionStartIncluding": "13.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*",
            "matchCriteriaId": "FCFFA1B3-87CE-4CC8-990E-D3CE0B55CD45",
            "versionEndExcluding": "13.1.37.279",
            "versionStartIncluding": "13.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*",
            "matchCriteriaId": "1CA9588A-E3EB-44FC-9515-6EB89BB8C1D6",
            "versionEndExcluding": "14.1-73.37",
            "versionStartIncluding": "14.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*",
            "matchCriteriaId": "046FF602-D956-4961-89BF-2041A3590004",
            "versionEndIncluding": "14.1-73.37",
            "versionStartIncluding": "14.1-66.68",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "3286D2C3-EA7E-4D9C-95DE-05D462DC8B1B",
            "versionEndExcluding": "13.1-64.23",
            "versionStartIncluding": "13.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "C77243A7-1FDB-4557-88BE-EDF3BAA56A81",
            "versionEndExcluding": "14.1-73.37",
            "versionStartIncluding": "14.1",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.