CVE-2026-75602

OpenList: Authenticated arbitrary file write via Content-Disposition path traversal in SimpleHttp offline-download tool

The minimal, deployment-agnostic guarantee is: the attacker can cause the application to create or overwrite files whose parent directory exists, with content of their choice, as the alist process (PUID=0 in default Docker). Because the vulnerable code ultimately calls os.Create on the attacker-controlled resolved path, existing files may be truncated and replaced when the target already exists. Concrete impact paths include:

• Replace /opt/alist/data/config.json with attacker config (alternative JwtSecret, admin password hash, allowed origins), admin takeover on next restart / config-reload hook.
• Drop a webshell into a writable docroot served by a sibling web server (environment-dependent).
• Truncate the alist binary at /opt/alist/alist (Linux permits overwriting an executing binary on most filesystems), next start runs attacker's binary.
• Write authorized_keys if a host volume bind-mounts e.g. /root/.ssh and that directory exists.

Caveat: the parent directory of the target must already exist; os.Create does not mkdir -p intermediate components. This still leaves many high-impact targets reachable on default deployments.

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-2026-75602 has a CVSS score of 6.5 (Medium). The vector is network-reachable, high 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 (4.2.3); upgrading removes the vulnerable code path.

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Minimal patch in internal/offline_download/http/util.go:

filename = filepath.Base(filename)
if filename == "" || filename == "." || filename == ".." || !filepath.IsLocal(filename) {
    return "", fmt.Errorf("invalid filename in Content-Disposition: [%s]", contentDisposition)
}
return filename, nil

Defense-in-depth in internal/offline_download/http/client.go after computing filePath:

cleanTempDir := filepath.Clean(task.TempDir) + string(filepath.Separator)
if !strings.HasPrefix(filepath.Clean(filePath)+string(filepath.Separator), cleanTempDir) {
    return fmt.Errorf("filename escapes temp dir")
}

Additionally, file creation should reject existing targets (or use an equivalent exclusive-create mechanism) to prevent accidental or attacker-controlled overwrites when a chosen filename resolves to an existing file.

if _, err := os.Stat(filePath); err == nil {
    return fmt.Errorf("file already exists")
}

The same Content-Disposition / URL-derived filename trust pattern should be reviewed in the other offline-download tools under internal/offline_download/{aria2,qbit,transmission,115,pikpak,thunder}/ for consistency.

1. What is CVE-2026-75602? CVE-2026-75602 is a medium-severity path traversal vulnerability in github.com/OpenListTeam/OpenList (go), affecting versions <= 4.2.2. It is fixed in 4.2.3. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-75602? CVE-2026-75602 has a CVSS score of 6.5 (Medium). 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/OpenListTeam/OpenList are affected by CVE-2026-75602? github.com/OpenListTeam/OpenList (go) versions <= 4.2.2 is affected.
4. Is there a fix for CVE-2026-75602? Yes. CVE-2026-75602 is fixed in 4.2.3. Upgrade to this version or later.
5. Is CVE-2026-75602 exploitable, and should I be worried? Whether CVE-2026-75602 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-2026-75602 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-2026-75602? Upgrade github.com/OpenListTeam/OpenList to 4.2.3 or later.