CVE-2026-23944: Unauthenticated Remote Environment Access in Arcane Docker Manager

Vulnerability overview

CVE ID: CVE-2026-23944
Product: Arcane (Docker management platform)
Vulnerability type: Authentication Bypass / Missing Authentication
Affected versions: All Arcane versions prior to v1.13.2
Fixed version: v1.13.2
CVSS v4.0 score: 8.0 (High)
Severity: High to Critical (depending on exposure)
Attack vector: Network
Privileges required: None
User interaction: None
Exploit maturity: No public exploit at the time of writing
Exploit availability: No confirmed public exploit; exploitation is technically simple
Impact: Unauthorized access to remote Docker environments

Executive summary

CVE-2026-23944 is a serious authentication bypass issue in Arcane, a web-based Docker management tool. The flaw exists in how Arcane proxies API requests to remote environments (Docker agents that are not local to the Arcane manager).

Due to a logic error, Arcane would forward certain API requests to remote agents without validating whether the original requester was authenticated. While forwarding the request, Arcane automatically attached its own internal agent token. This caused the remote agent to trust the request and execute it as if it came from a legitimate, authenticated Arcane administrator.

In simple terms:
If an attacker could reach the Arcane web interface, they could directly access and interact with remote Docker environments without logging in at all.

Technical root cause

The issue lies in Arcane’s environment proxy middleware:

Arcane distinguishes between local and remote environments.
For remote environments, requests are forwarded (proxied) from the Arcane manager to a remote agent.
The proxy logic incorrectly assumed that authentication had already occurred.
As a result:
- Requests to /api/environments/{environment_id}/... were proxied even when no user authentication was present.
- The manager automatically appended a valid agent authentication token.
- The remote agent trusted the token and executed the request.

This is a classic case of missing authentication for a critical function.

How this vulnerability can be exploited

The following explanation is for defensive and educational purposes only.

Attack prerequisites

Network access to the Arcane management interface (internal or internet-exposed).
Knowledge or guessability of a valid remote environment ID.

Example exploitation flow

An attacker sends a direct HTTP request to Arcane: GET /api/environments/3/containers No authentication headers or session cookies are included.
Arcane identifies environment ID 3 as a remote environment.
Instead of rejecting the request, Arcane proxies it to the remote agent.
Arcane automatically attaches its internal agent token.
The remote agent processes the request as trusted and returns data such as:
- Container lists
- Container status
- Logs
- Agent API responses
The response is sent back to the attacker.

This process can be repeated across multiple endpoints depending on the agent’s exposed API surface.

Potential impact

If exploited, this vulnerability can lead to:

Information disclosure
- Container metadata
- Application logs
- Environment variables
- Secrets accidentally written to logs
Operational impact
- Starting or stopping containers
- Restarting services
- Triggering maintenance or debug endpoints
Security escalation
- Access to containers mounting sensitive volumes
- Abuse of containers with access to the Docker socket
- Possible host-level compromise depending on container configuration
Lateral movement
- If multiple remote environments are managed, attackers may pivot across systems

MITRE mapping

Weakness classification

CWE-306 – Missing Authentication for Critical Function

Likely ATT&CK techniques

T1190 – Exploit Public-Facing Application
T1087 / T1083 (post-access) – Discovery of containers, services, and environment data
T1059 (context-dependent) – Command execution through container or agent misuse

Proof of concept (PoC) status

No public PoC is currently available
Exploitation does not require memory corruption, race conditions, or complex payloads
A functional PoC would only require crafted HTTP requests to vulnerable proxy endpoints
This makes the issue low effort to exploit once discovered by attackers

Detection and monitoring guidance

Key log sources to monitor

Arcane application logs
Arcane API access logs
Reverse proxy logs (Nginx, Traefik, Apache)
Remote Docker agent logs
Network firewall / WAF logs

Indicators of compromise or probing

Requests to /api/environments/* with:
- No Authorization header
- No session cookie
- Successful HTTP responses (200 OK)
Unexpected access to:
- /containers
- /logs
- /stats
- Agent-specific endpoints
Activity from unknown or external IP addresses
Agent activity during off-hours or outside normal admin behavior

Example detection logic

Unauthenticated access pattern

Request URI contains /api/environments/
AND Authorization header is missing
AND Response status is 200

Suspicious proxy behavior

Proxy logs show forwarded requests
AND original request has no authenticated user context

Agent-side anomaly

Agent receives manager-token requests
AND no corresponding admin login event exists

Example exploitation payloads (educational)

GET /api/environments/5/containers
GET /api/environments/5/logs?tail=100
GET /api/environments/5/stats

If vulnerable, these requests may return valid data without authentication.

Remediation and patching

Official fix (recommended)

Upgrade Arcane to version 1.13.2 or later.

Official patch / upgrade link:
https://github.com/arcane/arcane/releases/tag/v1.13.2

Temporary mitigation

Restrict network access to Arcane:
- Internal-only access
- VPN-only access
- IP allowlisting
Place Arcane behind an authenticated reverse proxy
Monitor logs aggressively for unauthenticated API access
Rotate agent tokens after patching

These mitigations reduce risk but do not fully eliminate it.

Post-patch validation checklist

Confirm unauthenticated requests now return 401 or 403
Verify proxy middleware enforces authentication
Review logs for historical suspicious access
Rotate credentials and secrets used in managed environments
Audit containers for unauthorized changes

Final takeaway

CVE-2026-23944 is a high-impact, low-complexity authentication bypass that directly affects the security boundary between Arcane and managed Docker environments. While no public exploit is currently available, the vulnerability is straightforward and attractive for attackers, especially if Arcane is exposed to untrusted networks.

Immediate upgrade is strongly advised.