CASCACascade Atlas

Evidence dossier

CVE-2026-55255

Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow

62.5–77.5Priority evidence range
As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

State
PUBLISHED
Published
Jun 23, 2026
Updated
Jul 8, 2026
Evidence coverage
85%
CISA KEVCatalog member

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

FIRST EPSS0.56%

2026-07-18 · v2026.06.15 · percentile 42.8%

Source stateNo scored conflict

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

CISA-ADPindependent enrichment
container

CISA ADP Vulnrichment

GitHub_Moriginal assertion
container

Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow

CISA KEVoriginal assertion
observed_exploitation

Langflow Authorization Bypass Through User-Controlled Key Vulnerability

FIRST EPSSoriginal assertion
model_probability

Probability 0.005600000000; percentile 0.428420000000

Applicability

Cited product scope

Trace impact →
langflow-ailangflow
[{"status": "affected", "version": "< 1.9.1"}]unknown
Unknown vendorUnknown product
cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*; end excluding 1.9.1supported

Assessments

CVSS by origin

8.4
security-advisories@github.comCVSS 3.1 · role SecondaryCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L
8.4
GitHub_MCVSS 3.1 · role unknownCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

Limitations and unknowns

  • 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; unresolved scope remains unknown.
  • NVD-carried upstream facts remain derivative and are not independent corroboration.
  • 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.
  • Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.