CVE intelligence and bounded remediation
CVE-2021-21402 — Jellyfin is a Free Software Media System
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.
- Severity
- High
- CVSS
- 7.7 (3.1)
- Published
- 2021-03-23
- CISA KEV
- Not currently listed
- Ecosystem
- windows/system
- Weaknesses
- CWE-22
Affected products
- jellyfin / jellyfin
Matched remediation archetype
Path traversal, unsafe upload, and file handling
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
- Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
- Review canonicalization and containment checks across supported operating systems and storage backends.
Remediate safely
- Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
- Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
- Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.
Authoritative sources
Complete CVE record and remediation plan
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