CASCACascade Atlas

Evidence dossier

CVE-2026-67279

SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

Exploited in the wild (CISA KEV since Sep 25, 2026). CERT-PL reports CVSS 4.0 6.9. EPSS estimates 1.0% exploit likelihood as of Oct 22, 2026.

59.3–65.4Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request. On affected builds the server dispatches the command, enabling unauthenticated creation, overwrite, and reconstruction of files in the RouterOS managed file namespace, including support files containing configuration and diagnostic data.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

State
PUBLISHED
Published
Sep 5, 2026
Updated
Sep 26, 2026
Evidence coverage
85%

Evidence chronology

What was known when

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  1. Source dateSource date omittedFirst observed by CASCA
    CERT-PL

    Record text: SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

    Inspect raw assertion
    Field
    container
    Value
    SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
    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 dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 1.05% probability · 63.87th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.010460000000; percentile 0.638690000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Sep 25, 2026 · first observed Oct 22, 2026

Exploit likelihood1.05%

FIRST EPSS · score date Oct 22, 2026 · 63.9th percentile · first observed Oct 22, 2026

SeverityCVSS 6.9

CERT-PL · CVSS 4.0 · first observed Sep 26, 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 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 assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Oct 22, 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
Oct 22, 2026
Resolution
Resolve identity

Source comparison

Who said what

CERT-PLOriginal assertion
Record text

SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

Inspect raw assertion
Field
container
Value
SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
Source dateSource date omittedFirst 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 ↗
CISA KEVOriginal assertion
Exploitation cataloged

Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

1.05% probability · 63.87th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.010460000000; percentile 0.638690000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

4 scope groups

CERT-PL · source assertedMikrotikRouterOSDirect source scope
Affected: 7.24 to before 7.24.2 (custom comparison)Affected: 7.0.0 to before 7.23.4 (custom comparison)Affected: 6.0.0 to before 6.49.21 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "7.24", "lessThan": "7.24.2", "versionType": "custom"}, {"status": "affected", "version": "7.0.0", "lessThan": "7.23.4", "versionType": "custom"}, {"status": "affected", "version": "6.0.0", "lessThan": "6.49.21", "versionType": "custom"}]
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*; start including 6.0; end excluding 6.49.21
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*; start including 7.0; end excluding 7.23.4
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*; start including 7.24; end excluding 7.24.2

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
64c92c53-e578-4f8b-9bdc-4ce3d4121f55
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
3
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Oct 22, 2026
Retained assertion IDs
2acbccd3-c284-40b8-b9aa-5900cfd167e0407a6e8e-851e-4be8-b7db-5389b2258dcde55ecbbc-b38e-49e7-9777-be39764aa90a

Assessments

CVSS by origin

6.5
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
6.9
cvd@cert.plCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/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
6.9
CERT-PLCVSS 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:L/VI:L/VA:N/SC:N/SI:N/SA:N

Direct CVE/CNA normalized decisions

6.9Priority eligible

CERT-PL

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
Validation
Valid match
Recomputed
6.9
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.