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CVE-2026-17626 is a high-severity vulnerability affecting IBM Langflow OSS versions 1.0.0 through 1.10.3. The flaw resides in the way Langflow handles Docker-based MCP (Model Context Protocol) server creation. When an authenticated user submits a request to spin up an MCP server, Langflow passes user-supplied parameters directly to the Docker daemon without adequate validation or sanitization. Specifically, the application fails to filter dangerous volume-mount (-v, --volume) and device-mapping (--device) arguments. This oversight allows an attacker to craft a malicious MCP server configuration that mounts arbitrary host directories—such as /etc, /root, /home, or /var—into the container. Because the container runs with the same privileges as the Langflow process (often root or with extensive host access), the attacker can read, modify, or exfiltrate sensitive files from the underlying host operating system.
The technical root cause is improper input validation at the Docker orchestration layer, aligning with CWE-20 (Improper Input Validation) and CWE-266 (Incorrect Privilege Assignment). Langflow accepts JSON or API parameters that include Docker run options, but it does not enforce a denylist or allowlist for mount paths or device mappings. An authenticated attacker can thus supply a payload like `{“volume”: “/etc:/mnt/host”}` or `{“device”: “/dev/sda1:/dev/xda”}` to gain host filesystem access or raw block device interaction. The attack vector is network-based, requires low privileges (authenticated user), and has low complexity, making it highly attractive for malicious actors. The impact is catastrophic: full read/write access to host files, credential theft (e.g., /etc/shadow, SSH private keys), configuration leakage, and potential privilege escalation to host root. The vulnerability was discovered by Thai Son Dinh (VinSOC Labs) and published on August 5, 2026. IBM has acknowledged the issue and released a patched version, 1.10.4, which enforces strict filtering of Docker arguments and implements an allowlist for permitted mount paths. Until patched, organizations should disable MCP server functionality or restrict MCP creation to trusted administrators only.
DailyCVE Form:
Platform: IBM Langflow OSS
Version: 1.0.0–1.10.3
Vulnerability: Docker volume-mount injection
Severity: High (CVSS 8.8)
date: 2026-08-05
Prediction: 2026-08-10 (expected patch)
What Undercode Say:
Check vulnerable version
langflow --version
Verify Docker MCP endpoint exposure
curl -X GET http://target:7860/api/v1/mcp/servers -H "Authorization: Bearer $TOKEN"
Attempt to mount host /etc into container (exploit probe)
curl -X POST http://target:7860/api/v1/mcp/servers \
-H "Authorization: Bearer $TOKEN" \
-H "Content-Type: application/json" \
-d '{"name":"poc","docker_args":"-v /etc:/mnt/host"}'
Read /etc/passwd from mounted volume inside container
docker exec <container_id> cat /mnt/host/passwd
List all containers with dangerous mounts
docker ps --format "table {{.Names}}\t{{.Mounts}}" | grep -E "/etc|/root|/var"
Check for exposed device mappings
docker inspect <container_id> | jq '.[].HostConfig.Devices'
Monitor Docker API for suspicious volume/device requests
sudo journalctl -u docker --since "5 minutes ago" | grep -E "volume|device|bind"
Block dangerous mount paths via AppArmor or SELinux (temporary)
sudo aa-complain /etc/apparmor.d/docker
Exploit:
An authenticated attacker sends a crafted API request to the Langflow MCP server creation endpoint, injecting a `-v /host/path:/container/path` argument. The Langflow backend passes this unsanitized argument to the Docker daemon, which mounts the host directory into the container. The attacker then executes a shell inside the container (via `docker exec` or a reverse shell) and reads/writes sensitive host files. Example payload: {"docker_args":"-v /etc/shadow:/mnt/shadow"}. This grants access to password hashes, SSH keys, application secrets, and system configuration files. With write access, the attacker can modify /etc/passwd, plant cron jobs, or install backdoors, leading to full host compromise. No user interaction is required beyond valid authentication.
Protection:
- Upgrade to Langflow OSS 1.10.4 or later immediately.
- If patching is delayed, disable MCP servers entirely:
export LANGFLOW_DISABLE_MCP=true. - Restrict MCP server creation to trusted administrators using RBAC.
- Implement a Docker daemon configuration that denies all volume mounts except explicitly allowed paths (e.g., via `–mount` with read-only flags).
- Deploy network segmentation to limit Langflow access to trusted subnets.
- Use AppArmor/SELinux profiles to confine container capabilities and block host filesystem access.
- Enable audit logging for Docker API calls and monitor for anomalous `-v` or `–device` arguments.
- Apply least-privilege principles: run Langflow and its containers as non-root users.
Impact:
- Confidentiality: Attackers can read any host file, including
/etc/shadow, application configs, database credentials, and TLS private keys. - Integrity: Malicious modification of system binaries, cron entries, or authentication files can establish persistence and backdoors.
- Availability: Overwriting critical system files or device nodes can cause denial of service or system crashes.
- Lateral Movement: Exposed host files may contain credentials for other internal systems, enabling pivoting within the enterprise network.
- Compliance: Breaches of sensitive data (PII, PCI, HIPAA) may lead to regulatory fines and reputational damage.
- Operational Risk: Full container escape effectively grants host root access, undermining the security isolation that containers are meant to provide.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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