CVE-2026-104189: 3Dviewer-Nextcloud Missing Authentication

Description

The 3D Viewer for Nextcloud is a comprehensive 3D model viewer application for Nextcloud that supports multiple 3D file formats. In versions 1.7.9 through 3.3.1, the app's public file endpoint performed no share authorization. Anyone who knows a share token could read the shared file's contents even when the link share was protected by a password. `PublicFileController` extended `OCP\AppFramework\Controller` and marked its routes `#[PublicPage]`. Nextcloud only enforces share passwords through `PublicShareMiddleware`, which returns early for any controller that is not an `OCP\AppFramework\PublicShareController` instance — so no password, expiry, or share-type check ran for these routes. `ShareFileService::loadLinkShare()` compounded this by treating any token that `getShareByToken()` matched as authorised. A share token is the part of the URL that people paste into chats, emails, and tickets. Password protection exists precisely for the case where holding the token should not by itself grant access, and that guarantee did not hold. Requests to `GET /ocs/v2.php/apps/threedviewer/public/file/{token}/{fileId}` returned `200` with the full file body for password-protected shares, with no password and no session. Nextcloud's own share page correctly redirected such requests to the password prompt. Scope is limited to files in the formats this app handles (STL, GLB/glTF, OBJ, STEP, IFC, and the other supported 3D types). Non-3D files in the same share are unaffected. Expired shares returned `500` rather than leaking contents. This issue is fixed in 3.3.2. `PublicFileController` now extends `PublicShareController` and implements `isValidToken()`, `isPasswordProtected()`, and `getPasswordHash()`, delegating password and token validation to the framework and gaining brute-force throttling. `ShareFileService::findValidLinkShare()` additionally rejects share types other than link and email, rejects expired shares, and treats a `ShareNotFound` from the share manager as "no share" instead of letting it surface as a 500. As a workaround, disable the 3D Viewer app (`occ app:disable threedviewer`), or avoid relying on passwords to protect link shares that contain 3D model files, until you can upgrade.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.35%

28.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
maz1987in	3Dviewer-Nextcloud	>= 1.7.9, < 3.3.2

References

Timeline

Published: Oct 27, 2026
Last Modified: Oct 28, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-104189?

The 3D Viewer for Nextcloud is a comprehensive 3D model viewer application for Nextcloud that supports multiple 3D file formats. In versions 1.7.9 through 3.3.1, the app's public file endpoint performed no share authorization. Anyone who knows a share token could read the shared file's contents even when the link share was protected by a password. `PublicFileController` extended `OCP\AppFramework\Controller` and marked its routes `#[PublicPage]`. Nextcloud only enforces share passwords through `PublicShareMiddleware`, which returns early for any controller that is not an `OCP\AppFramework\PublicShareController` instance — so no password, expiry, or share-type check ran for these routes. `ShareFileService::loadLinkShare()` compounded this by treating any token that `getShareByToken()` matched as authorised. A share token is the part of the URL that people paste into chats, emails, and tickets. Password protection exists precisely for the case where holding the token should not by itself grant access, and that guarantee did not hold. Requests to `GET /ocs/v2.php/apps/threedviewer/public/file/{token}/{fileId}` returned `200` with the full file body for password-protected shares, with no password and no session. Nextcloud's own share page correctly redirected such requests to the password prompt. Scope is limited to files in the formats this app handles (STL, GLB/glTF, OBJ, STEP, IFC, and the other supported 3D types). Non-3D files in the same share are unaffected. Expired shares returned `500` rather than leaking contents. This issue is fixed in 3.3.2. `PublicFileController` now extends `PublicShareController` and implements `isValidToken()`, `isPasswordProtected()`, and `getPasswordHash()`, delegating password and token validation to the framework and gaining brute-force throttling. `ShareFileService::findValidLinkShare()` additionally rejects share types other than link and email, rejects expired shares, and treats a `ShareNotFound` from the share manager as "no share" instead of letting it surface as a 500. As a workaround, disable the 3D Viewer app (`occ app:disable threedviewer`), or avoid relying on passwords to protect link shares that contain 3D model files, until you can upgrade.

How severe is CVE-2026-104189?

CVE-2026-104189 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.35% probability of exploitation in the next 30 days.

How do I fix CVE-2026-104189?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →