CASCACascade Atlas

Evidence dossier

CVE-2026-88771

A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands

Exploited in the wild (CISA KEV since Sep 27, 2026). NetScaler reports CVSS 4.0 9.5. EPSS estimates 1.1% exploit likelihood as of Oct 22, 2026.

65.8–74.6Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

Improper input validation 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 leading to an unauthenticated attacker to execute arbitrary commands.

State
PUBLISHED
Published
Sep 27, 2026
Updated
Sep 29, 2026
Evidence coverage
85%

Evidence chronology

What was known when

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  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Citrix NetScaler Improper Input Validation Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Citrix NetScaler Improper Input Validation Vulnerability
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    CISA-ADP

    Record text: CISA ADP Vulnrichment

    Inspect raw assertion
    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    NetScaler

    Record text: A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands

    Inspect raw assertion
    Field
    container
    Value
    A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.08% probability · 64.92th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.010830000000; percentile 0.649210000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Sep 27, 2026 · first observed Sep 27, 2026

Exploit likelihood1.08%

FIRST EPSS · score date Oct 22, 2026 · 64.9th percentile · first observed Oct 22, 2026

SeverityCVSS 9.5

NetScaler · CVSS 4.0 · first observed Sep 29, 2026 · same-version scores align in this snapshot

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusLast verified source snapshot retained

The last verified source boundary remains in force for this claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
Review source contract
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Oct 22, 2026
Resolution
None
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Oct 22, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA KEVOriginal assertion
Exploitation cataloged

Citrix NetScaler Improper Input Validation Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Citrix NetScaler Improper Input Validation Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
CISA-ADPIndependent enrichment
Record text

CISA ADP Vulnrichment

Inspect raw assertion
Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
NetScalerOriginal assertion
Record text

A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands

Inspect raw assertion
Field
container
Value
A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.08% probability · 64.92th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.010830000000; percentile 0.649210000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

9 scope groups

NetScaler · source assertedCitrix NetScalerADCDirect source scope
Affected: 0 to before 14.1-73.37 (patch comparison)Affected: 0 to before 13.1-64.23 (patch comparison)Affected: 0 to before 14.1-73.37 FIPS (patch comparison)Affected: 0 to before 13.1.37.279 FIPS and NDcPP (patch comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "0", "lessThan": "14.1-73.37", "versionType": "patch"}, {"status": "affected", "version": "0", "lessThan": "13.1-64.23", "versionType": "patch"}, {"status": "affected", "version": "0", "lessThan": "14.1-73.37 FIPS", "versionType": "patch"}, {"status": "affected", "version": "0", "lessThan": "13.1.37.279 FIPS and NDcPP", "versionType": "patch"}]
NetScaler · source assertedCitrix NetScalerGatewayDirect source scope
Affected: 0 to before 14.1-73.37 (patch comparison)Affected: 0 to before 13.1-64.23 (patch comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "affected", "version": "0", "lessThan": "14.1-73.37", "versionType": "patch"}, {"status": "affected", "version": "0", "lessThan": "13.1-64.23", "versionType": "patch"}]
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*; start including 13.1; end excluding 13.1-64.23
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*; start including 14.1; end excluding 14.1-73.37
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*; start including 13.1; end excluding 13.1.37.279
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*; start including 14.1-66.68; end including 14.1-73.37
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*; start including 13.1; end excluding 13.1.37.279
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*; start including 13.1; end excluding 13.1-64.23
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*; start including 14.1; end excluding 14.1-73.37

Affected-product evidence

Accepted scope and product mapping

0 canonical links · 2 source-reported links

Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
750ac7d9-3627-4584-963a-160b3620058fde30ff5f-1e95-413e-8a38-7530ced8c497
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Nvd cpe vulnerable target
Assertions
7
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
0040ce23-b484-44c4-8d96-07cdbc378be30171ff75-58d1-43ff-8098-5cb211c6e28b87cc684d-f4da-4e2a-af19-252587d9f6008cf95d39-115e-48f3-984f-ffb6c862b86c8d8cd06c-0136-41c1-b20c-9387344ad575b1404bc1-f2a1-46ce-a0aa-832229612d98cc2f7586-5b39-49e9-b4c1-10ab42c76858

Assessments

CVSS by origin

9.8
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.5
CVE Program sourceCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
9.5
NetScalerCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Direct CVE/CNA normalized decisions

9.5Priority eligible

NetScaler

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Validation
Valid match
Recomputed
9.5
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.