CVE-2026-104189: Missing Auth (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.29%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-306 Missing Authentication

CWE-863 Incorrect Authorization

References

Other References

https://github.com/maz1987in/3Dviewer-Nextcloud/commit/1b0ca86ff9a96b4e045cb379bc8b8c2fe05f2fae https://github.com/maz1987in/3Dviewer-Nextcloud/commit/2cfef0326afc56112b948b3fdf7e5c873fab4104 https://github.com/maz1987in/3Dviewer-Nextcloud/releases/tag/v3.3.2 https://github.com/maz1987in/3Dviewer-Nextcloud/security/advisories/GHSA-gjh8-x4wm-3cfj

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-104189? +

CVE-2026-104189 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-104189? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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