CASCACascade Atlas

Evidence dossier

CVE-2022-23131

Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML

Exploited in the wild (CISA KEV since Feb 22, 2022). NVD reports CVSS 3.1 9.8. EPSS estimates 95.7% exploit likelihood as of Aug 27, 2026.

85.0–88.2Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

In the case of instances where the SAML SSO authentication is enabled (non-default), session data can be modified by a malicious actor, because a user login stored in the session was not verified. Malicious unauthenticated actor may exploit this issue to escalate privileges and gain admin access to Zabbix Frontend. To perform the attack, SAML authentication is required to be enabled and the actor has to know the username of Zabbix user (or use the guest account, which is disabled by default).

State
PUBLISHED
Published
Jan 13, 2022
Updated
Oct 21, 2025
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
    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
    Zabbix

    Record text: Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML

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    Field
    container
    Value
    Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Zabbix Frontend Authentication Bypass Vulnerability

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

    EPSS score: 95.68% probability · 99.87th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.956830000000; percentile 0.998650000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Feb 22, 2022 · first observed Jul 19, 2026

Exploit likelihood95.68%

FIRST EPSS · score date Aug 27, 2026 · 99.9th percentile · first observed Aug 27, 2026

SeverityCVSS 9.8

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

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

Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML

Inspect raw assertion
Field
container
Value
Unsafe client-side session storage leading to authentication bypass/instance takeover via Zabbix Frontend with configured SAML
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Zabbix Frontend Authentication Bypass Vulnerability

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

95.68% probability · 99.87th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.956830000000; percentile 0.998650000000
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

Zabbix · source assertedZabbixFrontendDirect source scope
Affected: 5.4.0 - 5.4.8Unaffected: 5.4.9 to before 5.4.9* (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "5.4.0 - 5.4.8"}, {"status": "unaffected", "version": "5.4.9", "lessThan": "5.4.9*", "versionType": "custom"}]
NVD CPE · APPLICATIONzabbixzabbixVulnerable target · 2 assertions
Any version (unconstrained) (>= 5.4.0, <= 5.4.8); Version 6.0.0Canonical identity product-24f6fc0bb782c62075be431133b9cfd15a68b633af8a4120b86e8af19dd65bb2Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:a:zabbix:zabbix:6.0.0:alpha1:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    No explicit bounds
    Match ID
    0dc67b03-af43-45c9-8eac-d60da5887712
  2. cpe:2.3:a:zabbix:zabbix:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 5.4.0; through including 5.4.8
    Match ID
    19429f9a-8623-4ba9-984b-4982418c21cd

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-cbcf596ba6e26ef80acd5eadb84377fadcfb2c98340a1b6e2d73da4f6dd95e14 · product-24f6fc0bb782c62075be431133b9cfd15a68b633af8a4120b86e8af19dd65bb2

Source class
Nvd cpe vulnerable target
Assertions
2
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
8473ecd4-aed0-4438-a779-4d0ca4fbf9dd9fd63b68-09bc-4002-800d-5f9498c901f8
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
8eee18bb-7291-4a09-8235-7ac639c32492

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
5.1
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:H/Au:N/C:P/I:P/A:P
9.1
security@zabbix.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.1
ZabbixCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Direct CVE/CNA normalized decisions

9.1Priority eligible

Zabbix

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Validation
Valid match
Recomputed
9.1
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.