CASCACascade Atlas

Evidence dossier

CVE-2026-94127

BIG-IP APM OAuth vulnerability

Exploited in the wild (CISA KEV since Sep 22, 2026). f5 reports CVSS 4.0 9.3. EPSS estimates 2.2% exploit likelihood as of Oct 22, 2026.

66.2–72.4Priority evidence range
Evidence through Oct 22, 2026, 6:07 PM UTC

As of Oct 22, 2026

Normalized restatement

When a BIG-IP APM access policy and an OAuth profile are configured on a virtual server, specific malicious traffic can lead to remote code execution (RCE). This vulnerability is only present when BIG-IP APM is configured as an OAuth Authorization Server. Deployments using APM strictly as an OAuth Client / Resource Server (without OAuth authorization server profiles configured) are not affected by this vulnerability. Impact: This vulnerability allows an unauthenticated attacker to perform remote code execution. The BIG-IP system in Appliance mode is also vulnerable. This is a data plane issue; there is no control plane exposure. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

State
PUBLISHED
Published
Sep 22, 2026
Updated
Sep 23, 2026
Evidence coverage
85%

Evidence chronology

What was known when

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  1. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    F5 BIG-IP APM Heap-based Buffer Overflow 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
    f5

    Record text: BIG-IP APM OAuth vulnerability

    Inspect raw assertion
    Field
    container
    Value
    BIG-IP APM OAuth vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 2.23% probability · 82.59th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.022260000000; percentile 0.825870000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Sep 22, 2026 · first observed Sep 23, 2026

Exploit likelihood2.23%

FIRST EPSS · score date Oct 22, 2026 · 82.6th percentile · first observed Oct 22, 2026

SeverityCVSS 9.3

f5 · CVSS 4.0 · first observed Sep 23, 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

CISA KEVOriginal assertion
Exploitation cataloged

F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
F5 BIG-IP APM Heap-based Buffer Overflow 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 ↗
f5Original assertion
Record text

BIG-IP APM OAuth vulnerability

Inspect raw assertion
Field
container
Value
BIG-IP APM OAuth vulnerability
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

2.23% probability · 82.59th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.022260000000; percentile 0.825870000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →

4 scope groups

f5 · source assertedF5BIG-IPDirect source scope
Affected: 21.1.0 to before Hotfix-BIGIP-21.1.0.2.0.30.22-ENG (custom comparison)Affected: 17.5.0 to before Hotfix-BIGIP-17.5.1.9.0.160.12-ENG (custom comparison)Affected: 17.1.0 to before Hotfix-BIGIP-17.1.3.5.0.41.14-ENG (custom comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "21.1.0", "lessThan": "Hotfix-BIGIP-21.1.0.2.0.30.22-ENG", "versionType": "custom"}, {"status": "affected", "version": "17.5.0", "lessThan": "Hotfix-BIGIP-17.5.1.9.0.160.12-ENG", "versionType": "custom"}, {"status": "affected", "version": "17.1.0", "lessThan": "Hotfix-BIGIP-17.1.3.5.0.41.14-ENG", "versionType": "custom"}]
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 17.0.0; end including 17.1.3
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:f5:big-ip_access_policy_manager:*:*:*:*:*:*:*:*; start including 17.5.0; end including 17.5.1
NVD · source assertedVendor unspecified by sourceProduct unspecified by sourceDirect source scope
Version bounds not stated
Scope supported
Inspect raw assertioncpe:2.3:a:f5:big-ip_access_policy_manager:21.1.0:*:*:*:*:*:*:*

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
a3342900-4cbe-4464-ae4c-71f760f452df
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
00733e74-2802-44a0-8647-7bd79062d70710173f58-f660-4646-8ed4-c70045b7e858a415927b-2bf6-41af-9b68-abbfc63957a3

Assessments

CVSS by origin

9.3
f5sirt@f5.comCVSS 4.0 · role Secondary · priority eligiblevalid_matchCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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
9.8
f5sirt@f5.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:H
9.3
f5CVSS 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:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8
f5CVSS 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:H

Direct CVE/CNA normalized decisions

9.3Priority eligible

f5

CVSS 4.0 · Primary · Original assertion · rank 1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Validation
Valid match
Recomputed
9.3
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1
9.8Priority eligible

f5

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:H
Validation
Valid match
Recomputed
9.8
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.