# CVE-2026-42883: Audiobookshelf: Cross-library file exfiltration via unscoped bulk download endpoint

> Authenticated users can exfiltrate files from unauthorized libraries via the bulk download endpoint due to missing access controls.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 May 2026
- **Updated:** 12 May 2026

## What is CVE-2026-42883?

CVE-2026-42883 is a medium-severity missing authorization vulnerability in advplyr audiobookshelf, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Audiobookshelf is a self-hosted audiobook and podcast server. Prior to 2.32.2, the GET /api/libraries/:id/download endpoint validates that the requesting user has access to the library specified in the URL path, but fetches downloadable items solely by attacker-provided IDs without constraining them to that library. An authenticated user with download permission and access to any one library can exfiltrate the full file contents of items belonging to any other library, including libraries they are explicitly denied access to. This vulnerability is fixed in 2.32.2.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-42883?


## How do I fix CVE-2026-42883?

No fix has been published for CVE-2026-42883 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42883 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42883 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42883 and fix it if it is affected.

What it is: CVE-2026-42883 is a medium-severity missing authorization vulnerability in advplyr audiobookshelf, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42883 exists.

Affected product: advplyr audiobookshelf. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42883/ (Markdown: https://insights.sbomify.com/CVE-2026-42883/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42883
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42883
- OSV: https://osv.dev/vulnerability/CVE-2026-42883

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42883/
Summaries are generated and may contain mistakes; the official description above is the record.