CASCACascade Atlas

Evidence dossier

CVE-2026-56290

Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0

Exploited in the wild (CISA KEV since Jul 7, 2026). Joomla reports CVSS 4.0 10.0. EPSS estimates 30.4% exploit likelihood as of Aug 26, 2026.

76.0–80.2Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0 - The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.

State
PUBLISHED
Published
Jun 29, 2026
Updated
Jul 23, 2026
Evidence coverage
85%

Evidence chronology

What was known when

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  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Joomlack Page Builder Improper Access Control Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Joomlack Page Builder Improper Access Control 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
    Joomla

    Record text: Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0

    Inspect raw assertion
    Field
    container
    Value
    Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 30.38% probability · 98.09th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.303750000000; percentile 0.980910000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Jul 7, 2026 · first observed Jul 19, 2026

Exploit likelihood30.38%

FIRST EPSS · score date Aug 26, 2026 · 98.1th percentile · first observed Aug 26, 2026

SeverityCVSS 10.0

Joomla · CVSS 4.0 · first observed Jul 27, 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

Joomlack Page Builder Improper Access Control Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Joomlack Page Builder Improper Access Control 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 ↗
JoomlaOriginal assertion
Record text

Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0

Inspect raw assertion
Field
container
Value
Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

30.38% probability · 98.09th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.303750000000; percentile 0.980910000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
1Underlying assertions
1Canonical products
1Target assertions
0Constraint assertions

Grouped from 1 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

2 scope groups

Joomla · source assertedjoomlack.frJoomlaCK.fr Page Builder CK extension for JoomlaDirect source scope
Affected: 1.0-3.6.0
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "1.0-3.6.0"}]
NVD CPE · APPLICATIONjoomlackpage_builder_ckVulnerable target · 1 assertions
Any version (unconstrained) (< 3.6.0)Canonical identity product-94efb228f30fcbb4da995a9b711ae6ad81c9c48e388c293308b52546f5476635Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:joomlack:page_builder_ck:*:*:*:*:*:joomla\!:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 3.6.0
    Match ID
    5181215d-df24-47ca-b49b-23bcb55c1c60

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
beecada8-6c29-4957-ad2e-26cc91d17104
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
a4a678a2-d827-42f4-a7e9-f5d4c81aa28b

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
10.0
security@joomla.orgCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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:Y/R:X/V:X/RE:X/U:Red
10.0
JoomlaCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red

Direct CVE/CNA normalized decisions

10.0Priority eligible

Joomla

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red
Validation
Valid match
Recomputed
10.0
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.