OpenList: Arbitrary File Read via Path Prefix Confusion in Share Creation API

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

OpenList a file list program that supports multiple storage. Prior to 4.2.4, the share creation and update checks in server/handles/sharing.go use strings.HasPrefix(requested_path, user.BasePath) without enforcing a directory separator boundary. An authenticated user with CanShare permission and a BasePath such as /base can submit a sibling path such as /base2/secret.txt, create a share for the out-of-scope file, and use the public share download or list handlers to read data outside the assigned directory. This issue is fixed in version 4.2.4.

Source published

18 Aug 2026 18:04:42 UTC

Source modified

18 Aug 2026 18:47:07 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

OpenList a file list program that supports multiple storage. Prior to 4.2.4, the share creation and update checks in server/handles/sharing.go use strings.HasPrefix(requested_path, user.BasePath) without enforcing a directory separator boundary. An authenticated user with CanShare permission and a BasePath such as /base can submit a sibling path such as /base2/secret.txt, create a share for the out-of-scope file, and use the public share download or list handlers to read data outside the assigned directory. This issue is fixed in version 4.2.4.

Source published

Aug 18, 2026, 6:04:42 PM (timezone not stated)

Source modified

Aug 18, 2026, 6:47:07 PM (timezone not stated)

Observed here

7 Nov 2026 14:21:15 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

OpenList a file list program that supports multiple storage. Prior to 4.2.4, the share creation and update checks in server/handles/sharing.go use strings.HasPrefix(requested_path, user.BasePath) without enforcing a directory separator boundary. An authenticated user with CanShare permission and a BasePath such as /base can submit a sibling path such as /base2/secret.txt, create a share for the out-of-scope file, and use the public share download or list handlers to read data outside the assigned directory. This issue is fixed in version 4.2.4.

Source published

18 Aug 2026 18:19:28 UTC

Source modified

22 Oct 2026 22:10:00 UTC

Observed here

25 Oct 2026 15:18:51 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

### Summary An authorization bypass vulnerability exists in the file sharing mechanism of `Openlist`. Due to a flawed, non-separator-aware path validation check, an authenticated user can create share links for files outside their restricted base directory. This allows an attacker to bypass tenant/user isolation and gain unauthorized read access to arbitrary files within the system. ### Details When a user attempts to create or update a file share, the application must verify that the requested file path falls within the user's assigned `BasePath`. However, in `server/handles/sharing.go`, this authorization check relies on a simple string prefix function: `strings.HasPrefix(requested_path, user.BasePath)`. Because `strings.HasPrefix` does not account for directory separators (e.g., `/`), an attacker whose `BasePath` is assigned to `/base` can supply a target path like `/base2/secret_document.txt`. The validation `strings.HasPrefix("/base2/secret_document.txt", "/base")` evaluates to `true`, successfully passing the authorization filter. Once the share is created, the public share download/list handlers unwrap and serve the file based on the stored absolute path without re-verifying the creator's current directory scope, granting the attacker horizontal access to unauthorized data. ### PoC **Prerequisites:** 1. A system with at least two distinct directories at the root level: `/base` and `/base2`. 2. A sensitive file exists at `/base2/secret.txt`. 3. An attacker account with the `CanShare` permission enabled and its `Base path` strictly limited to `/base`. **Exploitation Steps:** 1. Log in as the attacker account and obtain the JWT authorization token. 2. Send a `POST` request to create a new share, intentionally targeting the unauthorized sibling directory `/base2`: ```http POST /api/share/create HTTP/1.1 Host: <your-openlist-host> Authorization: <attacker-jwt-token> Content-Type: application/json { "files": ["/base2/secret.txt"], "pwd": "", "max_accessed": 0 } ``` Observe the bypass: The API accepts the request and responds with a successful share creation message, returning a `share_id`. The attacker can now access the public share endpoint (e.g., via the web UI or API `/api/fs/list` / `/sd/<share-id>/...`) to download or view `/base2/secret.txt`, completely bypassing their directory restrictions. <img width="2457" height="1307" alt="7b0bd29c9d12ad0b7b84a4a156559a5b" src="https://github.com/user-attachments/assets/415e4915-dbc2-4738-8c53-8174998b42a9" /> <img width="1937" height="856" alt="90b16bf15b6e8bfb87f16c4ab8864ea7" src="https://github.com/user-attachments/assets/8dc5205e-2ac6-4f4f-9d40-e1e9d72229d5" /> ### Impact This is a High-severity Horizontal and Vertical Privilege Escalation vulnerability. A malicious user with basic sharing privileges can weaponize this path confusion to expose, read, and download any file from other users' directories or internal application paths, provided the target path shares the same string prefix as their own directory. This completely breaks the data isolation guarantees of the application. ### Remediation Recommendations Canonical Path Containment: Replace the raw `strings.HasPrefix` check with a robust, separator-aware path containment validation. Ensure both paths are normalized, and use logic such as: `target == base || strings.HasPrefix(target, base + "/")`. Centralized Validation Utility: Implement a dedicated function (e.g., `utils.IsSubPath(base, target)`) and apply it consistently across share creation, updating, and viewing handlers to prevent regressions. ### Credits - Thai Son Dinh from VinSOC Labs (R&D)

Source published

24 Jul 2026 22:32:37 UTC

Source modified

18 Aug 2026 18:49:43 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Publisher rating · MODERATE

OpenList: Arbitrary File Read via Path Prefix Confusion in Share Creation API in github.com/OpenListTeam/OpenList

Source published

18 Aug 2026 14:32:29 UTC

Source modified

18 Aug 2026 18:49:43 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.