CASCACascade Atlas

Evidence dossier

CVE-2026-18577

Incomplete patch leads to administrative account takeover

Exploited in the wild (CISA KEV since Aug 3, 2026). N-able reports CVSS 4.0 8.2. EPSS estimates 54.1% exploit likelihood as of Aug 27, 2026.

75.2–80.5Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

An incomplete patch for CVE-2026-18556 allows for authentication bypass and account takeover in N-central Versions through 2026.3.1

State
PUBLISHED
Published
Aug 2, 2026
Updated
Aug 4, 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: Incomplete patch leads to administrative account takeover

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

    EPSS score: 54.07% probability · 98.93th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.540680000000; percentile 0.989260000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Aug 3, 2026 · first observed Aug 3, 2026

Exploit likelihood54.07%

FIRST EPSS · score date Aug 27, 2026 · 98.9th percentile · first observed Aug 27, 2026

SeverityCVSS 8.2

N-able · CVSS 4.0 · first observed Aug 4, 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

Incomplete patch leads to administrative account takeover

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

54.07% probability · 98.93th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.540680000000; percentile 0.989260000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

3 scope groups

N-able · source assertedN-ableN-centralDirect source scope
Affected: 0 through 2026.3 (custom comparison)Unaffected: 2026.3.1.7 (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": "2026.3"}, {"status": "unaffected", "version": "2026.3.1.7", "versionType": "custom"}]
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 excluding 2026.3
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:2026.3:-:*:*:*:*:*:*

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
24bf2d92-cb04-4f75-9dc8-7508dd16e086
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
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
9817ad1b-a7ac-4cd5-9f7f-bcea3944eb39af82324f-e075-4b17-b890-18ead0e13ff8

Assessments

CVSS by origin

8.1
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:H
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:L/SI:L/SA:L/E:A/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:L/SI:L/SA:L/E:A

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:L/SI:L/SA:L/E:A
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.