CASCACascade Atlas

Evidence dossier

CVE-2025-34291

Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE

Exploited in the wild (CISA KEV since May 21, 2026). VulnCheck reports CVSS 4.0 9.4. EPSS estimates 83.8% exploit likelihood as of Aug 27, 2026.

84.5–86.0Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

Langflow versions up to and including 1.6.9 contain a chained vulnerability that enables account takeover and remote code execution. An overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) combined with a refresh token cookie configured as SameSite=None allows a malicious webpage to perform cross-origin requests that include credentials and successfully call the refresh endpoint. An attacker-controlled origin can therefore obtain fresh access_token / refresh_token pairs for a victim session. Obtained tokens permit access to authenticated endpoints — including built-in code-execution functionality — allowing the attacker to execute arbitrary code and achieve full system compromise.

State
PUBLISHED
Published
Dec 5, 2025
Updated
Jul 14, 2026
Evidence coverage
92%

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: Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE

    Inspect raw assertion
    Field
    container
    Value
    Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE
    Original evidence ↗
  3. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Langflow Origin Validation Error Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Langflow Origin Validation Error Vulnerability
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 83.84% probability · 99.67th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.838440000000; percentile 0.996700000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date May 21, 2026 · first observed Jul 19, 2026

Exploit likelihood83.84%

FIRST EPSS · score date Aug 27, 2026 · 99.7th percentile · first observed Aug 27, 2026

SeverityCVSS 9.4

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

Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE

Inspect raw assertion
Field
container
Value
Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Langflow Origin Validation Error Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Langflow Origin Validation Error Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

83.84% probability · 99.67th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.838440000000; percentile 0.996700000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
1Underlying assertions
1Canonical products
1Target 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 assertedLangflowLangflowDirect source scope
Affected: 0 through 1.6.9 (semver comparison)
Source-reported scope

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

Inspect raw assertion[{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "1.6.9"}]
NVD CPE · APPLICATIONlangflowlangflowVulnerable target · 1 assertions
Any version (unconstrained) (<= 1.6.9)Canonical identity product-3ecad60d02e883a382324c9859efb83a91960bf7dc2691a11ef690e2ed0fd8b5Linked exact
Scope supported
Inspect raw assertion
  1. cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    through including 1.6.9
    Match ID
    1d74dc53-9772-4172-822e-3e29e5a4ddc9

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-d794a20dfd4d03a8ec8ec2f926b9d829efbfd8b314b92fe2c078ce4d5f3310c9 · product-3ecad60d02e883a382324c9859efb83a91960bf7dc2691a11ef690e2ed0fd8b5

Source class
Nvd cpe vulnerable target
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
10546aab-dbc4-4fbf-bc40-8aa2f2c1a549
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
5f00da55-70f3-4d3d-9ee9-77b107affc30

Assessments

CVSS by origin

8.8
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.4
disclosure@vulncheck.comCVSS 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: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
9.4
VulnCheckCVSS 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

Direct CVE/CNA normalized decisions

9.4Priority eligible

VulnCheck

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
Validation
Valid match
Recomputed
9.4
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.