CASCACascade Atlas

Evidence dossier

CVE-2026-18556

Unauthenticated administrative account takeover

Exploited in the wild (CISA KEV since Aug 4, 2026). N-able reports CVSS 4.0 8.2. EPSS estimates 40.2% exploit likelihood as of Aug 27, 2026.

73.2–77.4Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Authentication bypass using an alternate path or channel vulnerability in N-able N-central allows Authentication Bypass. This issue affects N-central: through 2026.1.

State
PUBLISHED
Published
Aug 1, 2026
Updated
Aug 5, 2026
Evidence coverage
85%

Evidence chronology

What was known when

Download this view's receipt →
  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    N-able N-central Authentication Bypass Using an Alternate Path or Channel 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
    N-able

    Record text: Unauthenticated administrative account takeover

    Inspect raw assertion
    Field
    container
    Value
    Unauthenticated administrative account takeover
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 40.16% probability · 98.53th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.401580000000; percentile 0.985290000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Aug 4, 2026 · first observed Aug 4, 2026

Exploit likelihood40.16%

FIRST EPSS · score date Aug 27, 2026 · 98.5th percentile · first observed Aug 27, 2026

SeverityCVSS 8.2

N-able · CVSS 4.0 · first observed Aug 6, 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 KEVOriginal assertion
Exploitation cataloged

N-able N-central Authentication Bypass Using an Alternate Path or Channel Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
N-able N-central Authentication Bypass Using an Alternate Path or Channel 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 ↗
N-ableOriginal assertion
Record text

Unauthenticated administrative account takeover

Inspect raw assertion
Field
container
Value
Unauthenticated administrative account takeover
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

40.16% probability · 98.53th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.401580000000; percentile 0.985290000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

2 scope groups

N-able · source assertedN-ableN-centralDirect source scope
Affected: 0 through 2026.1 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "0", "versionType": "custom", "lessThanOrEqual": "2026.1"}]
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:n-able:n-central:*:*:*:*:*:*:*:*; end including 2026.1

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
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
d62e9bef-288b-417d-b4e3-076d63b466fd
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
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
07a97fe1-6d1f-4282-80cc-01c80ba4b06c

Assessments

CVSS by origin

7.4
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
8.2
CVE Program sourceCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/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
8.2
N-ableCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Direct CVE/CNA normalized decisions

8.2Priority eligible

N-able

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Validation
Valid match
Recomputed
8.2
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.