CASCACascade Atlas

Evidence dossier

CVE-2026-48558

SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification

Exploited in the wild (CISA KEV since Jun 29, 2026). VulnCheck reports CVSS 4.0 9.5. EPSS estimates 12.4% exploit likelihood as of Aug 27, 2026.

73.4–75.0Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the OIDC authentication flow. When OIDC authentication is configured, identity tokens submitted during login are accepted without verifying their cryptographic signature. In a vulnerable configuration, a remote, unauthenticated attacker can submit a forged token containing arbitrary identity claims to obtain a fully authenticated technician session. In some configurations, this may also allow bypass of multi-factor authentication. No user interaction is required.

State
PUBLISHED
Published
Jun 12, 2026
Updated
Jul 14, 2026
Evidence coverage
95%

Evidence chronology

What was known when

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  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
    VulnCheck

    Record text: SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification

    Inspect raw assertion
    Field
    container
    Value
    SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: SimpleHelp Authentication Bypass Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    SimpleHelp Authentication Bypass Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 12.38% probability · 95.9th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.123810000000; percentile 0.959000000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Jun 29, 2026 · first observed Jul 19, 2026

Exploit likelihood12.38%

FIRST EPSS · score date Aug 27, 2026 · 95.9th percentile · first observed Aug 27, 2026

SeverityCVSS 9.5

VulnCheck · CVSS 4.0 · 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 ↗
VulnCheckOriginal assertion
Record text

SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification

Inspect raw assertion
Field
container
Value
SimpleHelp Authentication Bypass via Missing OIDC JWT Signature Verification
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

SimpleHelp Authentication Bypass Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
SimpleHelp Authentication Bypass Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

12.38% probability · 95.9th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.123810000000; percentile 0.959000000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
2Underlying assertions
1Canonical products
2Target 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

VulnCheck · source assertedSimpleHelpSimpleHelpDirect source scope
Affected: 5.5.0 to before 5.5.16 (semver comparison)Affected: 6.0 to before 6.0 RC2 (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "5.5.0", "lessThan": "5.5.16", "versionType": "semver"}, {"status": "affected", "version": "6.0", "lessThan": "6.0 RC2", "versionType": "custom"}]
NVD CPE · APPLICATIONsimple-helpsimplehelpVulnerable target · 2 assertions
Any version (unconstrained) (< 5.5.16); Version 6.0Canonical identity product-17fb34d7c4e23dfdd6c5b6bcf5a20690bff35948e6fbdd7df3e50c9117a7396fLinked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:simple-help:simplehelp:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through excluding 5.5.16
    Match ID
    60e78059-d944-49ad-b48d-0cfa8be13598
  2. cpe:2.3:a:simple-help:simplehelp:6.0:pre-release:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    4647570f-9368-4088-9e52-f63091c74b68

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-663efa86ad3db4776f4ba6d6dc4d7d0fc0b7a1f973a4800f22406b2dced91cac · product-17fb34d7c4e23dfdd6c5b6bcf5a20690bff35948e6fbdd7df3e50c9117a7396f

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
491edaf6-7b0e-41cf-b912-a3708bc95d007b37c22d-97e3-4b82-899d-69645bc433a0
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
062be2f4-93a6-46e5-a51b-fab43391fe79

Assessments

CVSS by origin

9.5
disclosure@vulncheck.comCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
10.0
disclosure@vulncheck.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
9.5
VulnCheckCVSS 4.0 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
10.0
VulnCheckCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

9.5Priority eligible

VulnCheck

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Validation
Valid match
Recomputed
9.5
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1
10.0Priority eligible

VulnCheck

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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.