CASCACascade Atlas

Evidence dossier

CVE-2021-26829

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

Exploited in the wild (CISA KEV since Nov 28, 2025). NVD reports CVSS 3.1 5.4. EPSS estimates 48.0% exploit likelihood as of Aug 26, 2026.

70.0–71.5Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

State
PUBLISHED
Published
Jun 11, 2021
Updated
Dec 2, 2025
Evidence coverage
95%

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
    CVE Program

    Record text: CVE Program Container

    Inspect raw assertion
    Field
    container
    Value
    CVE Program Container
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    mitre

    Record text: OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

    Inspect raw assertion
    Field
    container
    Value
    OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: OpenPLC ScadaBR Cross-site Scripting Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    OpenPLC ScadaBR Cross-site Scripting Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 48.05% probability · 98.77th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.480500000000; percentile 0.987650000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Nov 28, 2025 · first observed Jul 19, 2026

Exploit likelihood48.05%

FIRST EPSS · score date Aug 26, 2026 · 98.8th percentile · first observed Aug 26, 2026

SeverityCVSS 5.4

NVD · CVSS 3.1 · 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 ↗
CVE ProgramDerivative copy
Record text

CVE Program Container

Inspect raw assertion
Field
container
Value
CVE Program Container
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
mitreOriginal assertion
Record text

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

Inspect raw assertion
Field
container
Value
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

OpenPLC ScadaBR Cross-site Scripting Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
OpenPLC ScadaBR Cross-site Scripting Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

48.05% probability · 98.77th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.480500000000; percentile 0.987650000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
4Underlying assertions
3Canonical products
2Target assertions
2Constraint assertions

Grouped from 4 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

mitre · source assertedn/an/aDirect source scope
Affected: n/a
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "n/a"}]
NVD CPE · OPERATING SYSTEMlinuxlinux_kernelEnvironmental constraint · 1 assertions
Version not applicableCanonical identity product-0eda7a801761be4590f267cf319481c8c0aaa30546d99cc064edf77989ce05c9Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    0 · node/1 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    703af700-7a70-47e2-bc3a-7fd03b3ca9c1
NVD CPE · OPERATING SYSTEMmicrosoftwindowsEnvironmental constraint · 1 assertions
Version not applicableCanonical identity product-6a798dc931affc038ba266631a506d54b455ffebd96b4fae68f77b6bd7aef178Linked exact
Scope constrained
Inspect raw assertion
  1. cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Environmental constraint
    Configuration
    1 · node/1 · match 0
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    a2572d17-1de6-457b-99cc-64afd54487ea
NVD CPE · APPLICATIONscadabrscadabrVulnerable target · 2 assertions
Any version (unconstrained) (<= 0.9.1); Any version (unconstrained) (<= 1.12.4)Canonical identity product-27671e1f976449f0130f9c72e918f530153be222aff885201651252852b881e8Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    1 · node/0 · match 0
    Logic
    OR
    Version bounds
    through including 1.12.4
    Match ID
    edadc64f-c764-48a3-8af4-ce3af50b6f1f
  2. cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through including 0.9.1
    Match ID
    de4bebe0-2a0c-4b10-8e00-732da4bdd6bb

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-a71a8b1e40633b3656c3d3584710679b99a541ee41ee4f5ada3a549492051100 · product-27671e1f976449f0130f9c72e918f530153be222aff885201651252852b881e8

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
637abe0a-384d-4833-a2b5-ced0a4f21caeadc4070d-2f35-4376-8203-830d803f3cfb
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
9fb162a0-f36b-47a4-8483-42a30544edaf

Assessments

CVSS by origin

5.4
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4
CVE Program sourceCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4
CISA-ADPCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Direct CVE/CNA normalized decisions

5.4Priority eligible

CISA-ADP

CVSS 3.1 · Secondary · Independent enrichment · rank 2

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Validation
Valid match
Recomputed
5.4
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.