CASCACascade Atlas

Evidence dossier

CVE-2026-102489

Undisclosed RCE in Zammad v6.3 and higher

Exploited in the wild (CISA KEV since Oct 2, 2026). DIVD reports CVSS 4.0 9.4. Severity assessments differ within at least one CVSS version. EPSS estimates 1.3% exploit likelihood as of Oct 22, 2026.

64.0–69.9Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

Zammad versions 6.3.0 to 6.5.4 are vulnerable a session hijack vulnerability that leads to remote code execution as the zammad user. The bug is also present in version 7.0.0 to version 7.1.2, but not exploitable due to changes in the underlying framework.

State
PUBLISHED
Published
Sep 30, 2026
Updated
Oct 19, 2026
Evidence coverage
72%

Evidence chronology

What was known when

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  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Zammad GmbH Zammad Session Fixation Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Zammad GmbH Zammad Session Fixation 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
    DIVD

    Record text: Undisclosed RCE in Zammad v6.3 and higher

    Inspect raw assertion
    Field
    container
    Value
    Undisclosed RCE in Zammad v6.3 and higher
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.26% probability · 69.28th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.012550000000; percentile 0.692770000000
    Original evidence ↗

Assessments differ

NVD9.8CVSS 3.1 · source date omitted
csirt@divd.nl9.4CVSS 4.0 · source date omitted

Values are shown separately by source and CVSS version.

ExploitationCatalog member

CISA KEV · catalog date Oct 2, 2026 · first observed Oct 3, 2026

Exploit likelihood1.26%

FIRST EPSS · score date Oct 22, 2026 · 69.3th percentile · first observed Oct 22, 2026

SeverityAssessments differ

DIVD · CVSS 4.0 · first observed Oct 19, 2026 · values shown separately below

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusLast verified source snapshot retained

The last verified source boundary remains in force for this claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
Review source contract
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Oct 22, 2026
Resolution
None
Severity assessmentAssessments differ

Eligible assertions materially conflict and remain visible side by side.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Oct 22, 2026
Resolution
Resolve conflict
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Oct 22, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA KEVOriginal assertion
Exploitation cataloged

Zammad GmbH Zammad Session Fixation Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Zammad GmbH Zammad Session Fixation 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 ↗
DIVDOriginal assertion
Record text

Undisclosed RCE in Zammad v6.3 and higher

Inspect raw assertion
Field
container
Value
Undisclosed RCE in Zammad v6.3 and higher
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.26% probability · 69.28th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.012550000000; percentile 0.692770000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

4 scope groups

DIVD · source assertedZammad GmbHZammadDirect source scope
Unknown: * to before 6.3.0 (semver comparison)Affected: 6.3.0 to before 6.5.4 (semver comparison)Unknown: 7.0.0 to before 7.1.3 (semver comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "unknown", "version": "*", "lessThan": "6.3.0", "versionType": "semver"}, {"status": "affected", "version": "6.3.0", "lessThan": "6.5.4", "versionType": "semver"}, {"status": "unknown", "version": "7.0.0", "lessThan": "7.1.3", "versionType": "semver"}]
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope constrained
Inspect raw assertioncpe:2.3:a:docker:docker:-:*:*:*:*:*:*:*
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:zammad:zammad:*:*:*:*:*:*:*:*; start including 6.3.0; end including 6.5.4
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope constrained
Inspect raw assertioncpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*

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
Oct 22, 2026
Retained assertion IDs
38bd286c-74b8-44c6-9b58-142b8367b72d
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
Oct 22, 2026
Retained assertion IDs
4ddb7d1c-43f4-42a3-9ae2-9abb4c98478f

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
9.4
csirt@divd.nlCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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:C/RE:X/U:X
8.7
DIVDCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:A/AU:Y/V:C
9.4
DIVDCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/V:C

Direct CVE/CNA normalized decisions

9.4Priority eligible

DIVD

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/V:C
Validation
Valid match
Recomputed
9.4
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1
8.7Priority eligible

DIVD

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:A/AU:Y/V:C
Validation
Valid match
Recomputed
8.7
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.