# [CRIT] [GHSA / CRITICAL] CVE-2026-48519: Langflow: Unauthenticated RCE in Shareable Playgrounds

**Source:** GitHub Security Advisories
**Published:** 2026-06-16
**Article:** https://github.com/advisories/GHSA-v5ff-9q35-q26f

## Threat Profile

Langflow: Unauthenticated RCE in Shareable Playgrounds

### Summary
The "Shareable Playground" (or "Public Flows" in code) contains a critical RCE vulnerability.
Simply sharing a flow exposes the deployment to RCE risk by authenticated users.

Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe

### Details
Shareable Playground feature works by enabling the execution of workflows by unauthenticated users, by accessing a link.
Specifically, it enables the route `/api/v1/build_public_tmp` to…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-48519`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1204.002** — User Execution: Malicious File
- **T1059.006** — Command and Scripting Interpreter: Python
- **T1595.002** — Active Scanning: Vulnerability Scanning
- **T1059.004** — Command and Scripting Interpreter: Unix Shell

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Langflow CVE-2026-48519: POST to /api/v1/build_public_tmp with embedded Python code

`UC_34_2` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime values(Web.http_user_agent) as user_agents values(Web.status) as statuses from datamodel=Web where Web.url="*/api/v1/build_public_tmp*" Web.http_method IN ("POST","PUT") by Web.src, Web.dest, Web.url, Web.http_method | `drop_dm_object_name(Web)` | where like(url,"%/api/v1/build_public_tmp%") | rename src as src_ip, dest as langflow_host | sort - lastTime
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(7d)
| where RemoteUrl has "/api/v1/build_public_tmp" or AdditionalFields has "/api/v1/build_public_tmp"
| project Timestamp, DeviceName, RemoteIP, RemotePort, LocalIP, LocalPort, RemoteUrl,
          InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath,
          InitiatingProcessAccountName
| order by Timestamp desc
```

### Langflow exploit reconnaissance: clustered errors against /api/v1/build_public_tmp

`UC_34_3` · phase: **recon** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count as error_count values(Web.status) as statuses values(Web.http_user_agent) as user_agents values(Web.url) as urls min(_time) as firstTime max(_time) as lastTime from datamodel=Web where Web.url="*/api/v1/build_public_tmp*" Web.status>=400 by Web.src, Web.dest, span=10m | `drop_dm_object_name(Web)` | where error_count >= 10 | rename src as src_ip, dest as langflow_host | sort - lastTime
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(1d)
| where RemoteUrl has "/api/v1/build_public_tmp"
| summarize HitCount = count(), Hosts = make_set(DeviceName, 10), Procs = make_set(InitiatingProcessFileName, 5)
          by RemoteIP, bin(Timestamp, 10m)
| where HitCount >= 10
| order by Timestamp desc
```

### Langflow Python runtime spawning shell/subprocess children (post-exploit RCE)

`UC_34_4` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.parent_process_name IN ("python","python3","python.exe","uvicorn","gunicorn") OR Processes.parent_process="*langflow*") (Processes.process_name IN ("sh","bash","dash","zsh","cmd.exe","powershell.exe","pwsh","touch","curl","wget","nc","ncat","socat","chmod","base64") OR Processes.process IN ("*/tmp/pwned*","*touch /tmp/*","*touch /dev/shm/*","*bash -i*","*sh -c*")) by Processes.dest, Processes.user, Processes.parent_process_name, Processes.parent_process, Processes.process_name, Processes.process | `drop_dm_object_name(Processes)` | sort - lastTime
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName in~ ("python","python3","python.exe","uvicorn","gunicorn")
      or InitiatingProcessCommandLine has_any ("langflow","build_public_tmp")
| where FileName in~ ("sh","bash","dash","zsh","cmd.exe","powershell.exe","pwsh.exe","touch","curl","wget","nc","ncat","socat","chmod","base64")
      or ProcessCommandLine has_any ("/tmp/pwned","touch /tmp/","touch /dev/shm","bash -i","sh -c","-c \"import os\"","socket.socket","subprocess.Popen","os.system")
| project Timestamp, DeviceName, AccountName,
          ParentImage = InitiatingProcessFolderPath,
          ParentCmd = InitiatingProcessCommandLine,
          ChildImage = FolderPath,
          ChildCmd = ProcessCommandLine,
          SHA256
| order by Timestamp desc
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-48519: Langflow: Unauthenticated RCE in Shareable Pla

`UC_34_1` · phase: **install** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-48519: Langflow: Unauthenticated RCE in Shareable Pla ```
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_path="*/tmp/pwned*")
    by Filesystem.dest, Filesystem.user, Filesystem.process_name,
       Filesystem.file_path, Filesystem.file_name
| `drop_dm_object_name(Filesystem)`
```

**Defender KQL:**
```kql
// Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-48519: Langflow: Unauthenticated RCE in Shareable Pla
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FolderPath has_any ("/tmp/pwned"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-48519`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 5 use case(s) fired, 5 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.