CASCACascade Atlas

Evidence dossier

CVE-2025-6543

Memory overflow vulnerability leading to unintended control flow and Denial of Service

Exploited in the wild (CISA KEV since Jun 30, 2025). Citrix reports CVSS 4.0 9.2. EPSS estimates 10.1% exploit likelihood as of Aug 27, 2026.

72.9–75.1Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

State
PUBLISHED
Published
Jun 25, 2025
Updated
Feb 26, 2026
Evidence coverage
96%

Evidence chronology

What was known when

Download this view's receipt →
  1. 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 ↗
  2. Source dateSource date omittedFirst observed by CASCA
    Citrix

    Record text: Memory overflow vulnerability leading to unintended control flow and Denial of Service

    Inspect raw assertion
    Field
    container
    Value
    Memory overflow vulnerability leading to unintended control flow and Denial of Service
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 10.09% probability · 95.29th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.100940000000; percentile 0.952860000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Jun 30, 2025 · first observed Jul 19, 2026

Exploit likelihood10.09%

FIRST EPSS · score date Aug 27, 2026 · 95.3th percentile · first observed Aug 27, 2026

SeverityCVSS 9.2

Citrix · CVSS 4.0 · first observed Jul 19, 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 statusEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 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
Aug 27, 2026
Resolution
Resolve identity

Source comparison

Who said what

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 ↗
CitrixOriginal assertion
Record text

Memory overflow vulnerability leading to unintended control flow and Denial of Service

Inspect raw assertion
Field
container
Value
Memory overflow vulnerability leading to unintended control flow and Denial of Service
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

10.09% probability · 95.29th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.100940000000; percentile 0.952860000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
6Underlying assertions
2Canonical products
6Target assertions
0Constraint assertions

Grouped from 2 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

4 scope groups

Citrix · source assertedNetScalerADCDirect source scope
Affected: 14.1 to before 47.46 (patch comparison)Affected: 13.1 to before 59.19 (patch comparison)Affected: 13.1 FIPS and NDcPP to before 37.236 (patch comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "14.1", "lessThan": "47.46", "versionType": "patch"}, {"status": "affected", "version": "13.1", "lessThan": "59.19", "versionType": "patch"}, {"status": "affected", "version": "13.1 FIPS and NDcPP", "lessThan": "37.236", "versionType": "patch"}]
Citrix · source assertedNetScalerGatewayDirect source scope
Affected: 14.1 to before 47.46 (patch comparison)Affected: 13.1 to before 59.19 (patch comparison)Affected: 13.1 FIPS and NDcPP to before 37.236 (patch comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "14.1", "lessThan": "47.46", "versionType": "patch"}, {"status": "affected", "version": "13.1", "lessThan": "59.19", "versionType": "patch"}, {"status": "affected", "version": "13.1 FIPS and NDcPP", "lessThan": "37.236", "versionType": "patch"}]
NVD CPE · APPLICATIONcitrixnetscaler_application_delivery_controllerVulnerable target · 4 assertions
Any version (unconstrained) (>= 13.1, < 13.1-37.236); Any version (unconstrained) (>= 13.1, < 13.1-59.19); Any version (unconstrained) (>= 14.1, < 14.1-47.46)Canonical identity product-698b699e3cb954f9bb1c9b64d30a2b05877d903ca4042465e866b06d7d56b465Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    from including 14.1; through excluding 14.1-47.46
    Match ID
    4a26624d-7f3f-4fd7-ac50-c9bdca656f7b
  2. cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    from including 13.1; through excluding 13.1-59.19
    Match ID
    355dcb05-54e3-4c13-a74a-b27ce3f10597
  3. cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 13.1; through excluding 13.1-37.236
    Match ID
    0f079648-790a-4d18-908d-25ca575c5b46
  4. cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 13.1; through excluding 13.1-37.236
    Match ID
    cf89ad2e-8a0a-43a9-9eeb-83d595576775
NVD CPE · APPLICATIONcitrixnetscaler_gatewayVulnerable target · 2 assertions
Any version (unconstrained) (>= 13.1, < 13.1-59.19); Any version (unconstrained) (>= 14.1, < 14.1-47.46)Canonical identity product-22e4fbefa2f721b35fa638467110ee91acacd31f29e7473b059c6b09738443c7Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    1 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 13.1; through excluding 13.1-59.19
    Match ID
    598029c6-734c-450c-a7ec-495c72819e88
  2. cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    1 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 14.1; through excluding 14.1-47.46
    Match ID
    d977c8ae-4b4e-474d-abd6-f55f054e5b59

Affected-product evidence

Accepted scope and product mapping

2 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-613dd4bb79ad8759a10407fe624cb651bdb422f3f2780231736f064b614ee756 · product-22e4fbefa2f721b35fa638467110ee91acacd31f29e7473b059c6b09738443c7

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
8b093aae-6201-464d-ac6a-67de637131f7b1b5e253-6077-4a57-8782-35623ab32264
Mapping establishedEvidence supported

vendor-613dd4bb79ad8759a10407fe624cb651bdb422f3f2780231736f064b614ee756 · product-698b699e3cb954f9bb1c9b64d30a2b05877d903ca4042465e866b06d7d56b465

Source class
Nvd cpe vulnerable target
Assertions
4
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
6af7bc7e-629c-4d33-b2ec-032057070db1a040dee0-ad9d-44d8-8901-898987239e54a7414d73-416f-4bbf-8ad7-5d28ec0a522fed451fa1-556b-43ee-abab-e3c5329e899c
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
Aug 27, 2026
Retained assertion IDs
64cd0043-bba9-4841-8e94-f85b0a1453a5eebfc364-9167-422f-8d89-dee0c9e634c6

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
9.2
secure@citrix.comCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/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
9.2
CitrixCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

Direct CVE/CNA normalized decisions

9.2Priority eligible

Citrix

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
Validation
Valid match
Recomputed
9.2
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.