CVE-2026-47179

ProjectService.GetProjectFileContent returns the contents of any Docker Compose include directive declared in a project's compose file before any path-traversal validation runs. Because ProjectService.CreateProject writes attacker-supplied compose content to disk without validating include paths, an authenticated user can create a project whose compose file declares include: ['../../../../etc/passwd'], then read the include via the project file API. The result is arbitrary read of any file readable by the Arcane backend process, including /app/data/arcane.db (the SQLite database containing every user's password hash and API key), enabling escalation to admin and, via Arcane's Docker control plane, RCE on the host.

Details

Root cause #1, CreateProject writes compose content without validation (backend/internal/services/project_service.go:1605-1644):

func (s *ProjectService) CreateProject(ctx context.Context, name, composeContent string, envContent *string, user models.User) (*models.Project, error) {
    // ... directory setup ...
    if err := projects.SaveOrUpdateProjectFiles(projectsDirectory, projectPath, composeContent, envContent); err != nil {
        _ = s.db.WithContext(ctx).Delete(proj).Error
        return nil, fmt.Errorf("failed to save project files: %w", err)
    }
    // ...
}

Compare with UpdateProject (project_service.go:2494, :2577), which calls validateComposeContentForUpdate. That validator (line 2599) loads the compose with missingIncludeStubResourceLoaderInternal, which calls ValidateIncludePathForWrite (includes.go:139) and rejects includes outside the project directory. CreateProject bypasses this entirely, so any malicious include: array survives to disk.

Root cause #2, GetProjectFileContent reads include files before path validation (backend/internal/services/project_service.go:831-872):

includes, parseErr := projects.ParseIncludes(composeFile, envMap, true)
if parseErr == nil {
    for _, inc := range includes {
        if inc.RelativePath == relativePath {
            return project.IncludeFile{
                Path:         inc.Path,
                RelativePath: inc.RelativePath,
                Content:      inc.Content,    // <-- arbitrary file content returned here
            }, nil
        }
    }
}

fullPath := filepath.Join(proj.Path, relativePath)
// ... IsSafeSubdirectory check at line 870, never reached when include matches ...

Root cause #3, ParseIncludes reads include files from anywhere by design (backend/pkg/projects/includes.go:24-72):

// Security Model for Include Files:
// - READ: Docker Compose allows include files from anywhere (parent dirs, absolute paths, etc.)
//         We allow reading from any path to maintain compatibility with standard Docker Compose behavior
// - WRITE/DELETE: Restricted to files within the project directory only for security

parseIncludeItemInternal at includes.go:97-101 builds fullPath = filepath.Clean(filepath.Join(baseDir, includePath)) and os.ReadFile(fullPath) at line 105, no containment check. The returned RelativePath (line 124) is filepath.ToSlash(filepath.Clean(includePath)), which preserves ../../../../etc/passwd verbatim for the equality match in GetProjectFileContent.

Authorization surface: The handler GET /api/environments/{id}/projects/{projectId}/file (backend/internal/huma/handlers/projects.go:268-279) and POST /api/environments/{id}/projects (line 242-253) only declare BearerAuth/ApiKeyAuth. There is no admin-role gate on either handler, GetProjectFile (line 582) and CreateProject (line 524) simply call humamw.GetCurrentUserFromContext. The default user role assigned in users.go:223 is "user" (not admin), and that role is sufficient to exploit.

Resulting primitive: arbitrary read of any file readable by the Arcane backend process (uid/gid of the container). Sensitive targets include /app/data/arcane.db (SQLite containing argon2 password hashes and API keys for every user), /app/data/secrets/*, mounted host configuration, SSH keys (if mounted), and Docker socket-adjacent secrets.

• Arbitrary file read as the Arcane backend process for any authenticated user, including users with the lowest-privilege "user" role.
• Credential disclosure: arcane.db contains argon2 password hashes for every account (including admins) and API key material, supports offline cracking and direct token exfiltration.
• Privilege escalation: a "user"-role attacker can recover or replay admin credentials, then exercise full Arcane functionality (Docker container/exec/volume control), which on a typical deployment with the host Docker socket mounted is host RCE.
• Configuration / secret exposure: any environment files, OIDC client secrets, registry credentials, or files mounted into the container are reachable.
• The scope crosses the security authority of other user accounts (S:C), since one authenticated user reads credentials belonging to other users and to the admin.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-47179 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.19.4); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-47179? CVE-2026-47179 is a high-severity path traversal vulnerability in github.com/getarcaneapp/arcane/backend (go), affecting versions <= 1.19.3. It is fixed in 1.19.4. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-47179? CVE-2026-47179 has a CVSS score of 7.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/getarcaneapp/arcane/backend are affected by CVE-2026-47179? github.com/getarcaneapp/arcane/backend (go) versions <= 1.19.3 is affected.
4. Is there a fix for CVE-2026-47179? Yes. CVE-2026-47179 is fixed in 1.19.4. Upgrade to this version or later.
5. Is CVE-2026-47179 exploitable, and should I be worried? Whether CVE-2026-47179 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-47179 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-47179? Upgrade github.com/getarcaneapp/arcane/backend to 1.19.4 or later.