UnratedPublic exploit

IDOR in Langflow /api/v1/responses

IdentifiersCVE-2026-55255CWE-639

CVE-2026-55255 is an Insecure Direct Object Reference (IDOR) vulnerability in Langflow, a platform for building and deploying AI-powered agents and workflows. The flaw affects versions prior to 1.9.2 and is present in the /api/v1/responses endpoint. Due to insufficient authorization enforcement on flow ownership, an authenticated attacker can submit a request containing another user’s flow ID and cause Langflow to execute that victim-owned flow. The issue is described as stemming from missing ownership validation when resolving flows for execution through this endpoint.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an authenticated attacker to execute arbitrary flows owned by other users within the same Langflow instance. This can expose sensitive data handled by those flows, permit unauthorized use or manipulation of victim workflows, and consume compute or other resources associated with the victim’s flows. The provided context also characterizes confidentiality, integrity, and availability impact as high.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by tightly restricting access to authenticated users with a legitimate need, limiting network exposure of the Langflow instance, minimizing disclosure of flow identifiers, and monitoring for cross-user flow execution attempts or anomalous requests to /api/v1/responses. No fully effective workaround is provided in the available content; upgrading is the primary mitigation.

Remediation

Patch, then assume compromise.

Upgrade Langflow to version 1.9.2 or later, which fixes the vulnerable behavior in /api/v1/responses by enforcing proper ownership validation for flow resolution and execution. After upgrading, verify that the deployed instance is actually running the fixed version and that no older vulnerable nodes remain in service.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

LangflowLangflowapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

4 SOURCESView more in app

cvefeed high severityNews

Jun 23, 2026

CVE-2026-55255 - Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow

An IDOR vulnerability in Langflow's /api/v1/responses endpoint that allows an authenticated attacker to access and execute another user's flow by supplying the victim's flow ID.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-55255

NVD

nvd.nist.gov/vuln/detail/CVE-2026-55255

MITRE CWE · CWE-639

cwe.mitre.org