Jellyfin before 12.0 Path Traversal via Library VirtualFolders Endpoints
Affects Jellyfin before 12.0 on servers that have not yet completed the startup setup wizard, where anonymous access is granted. Fixed in 12.0.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 12.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 12.0.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Jellyfin, the open-source media server software, is affected. Remotely, without logging in, an attacker can delete or move directories on the server by supplying crafted library names, which can recursively wipe the data directory and the jellyfin.db database, but only before initial setup is completed.
Read the original description
Jellyfin before 12.0 contains a path traversal vulnerability in the DELETE /Library/VirtualFolders and POST /Library/VirtualFolders/Name endpoints that allows attackers to delete or move directories via unvalidated library names. Unauthenticated attackers can supply names like .. or absolute paths before setup completes to recursively delete the data directory and jellyfin.db.
Who should check
Teams running Jellyfin before 12.0, including newly installed servers that have not finished the setup wizard and are reachable on a network
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.3/10CVSS 8.3
- No patch0/5No signal
What would change the score
- Would score about 70 if added to CISA KEV
- Would score about 65 if CISA's SSVC rates exploitation active
- Would score about 30 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 12.0.
Workaround: Complete the setup wizard immediately after installation, keep a new server off untrusted networks until then, or block /Library/VirtualFolders at a reverse proxy until setup is complete
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126499 (Jellyfin before 12.0 Path Traversal via Library VirtualFolders Endpoints), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126499 (entry last updated 2026-11-11): Affected: - jellyfin jellyfin: fixed in 12.0 Fixed versions: 12.0. Conditions (all must be true for the bug to be hit): - Server has not yet completed the startup setup wizard (unauthenticated window) (source: https://github.com/jellyfin/jellyfin/security/advisories/GHSA-6828-c7cx-hvqm) - Jellyfin version below 12.0 (source: https://www.vulncheck.com/advisories/jellyfin-before-12.0-path-traversal-via-library-virtualfolders-endpoints) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: network access, no login, no user action. Workaround: Complete the setup wizard immediately after installation, keep a new server off untrusted networks until then, or block /Library/VirtualFolders at a reverse proxy until setup is complete (source: https://www.vulncheck.com/advisories/jellyfin-before-12.0-path-traversal-via-library-virtualfolders-endpoints) CISA KEV: CVE-2026-126499 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126499 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/jellyfin/jellyfin/security/advisories/GHSA-6828-c7cx-hvqm - https://github.com/jellyfin/jellyfin/commit/0c560b22ce73323329645b836c9910abc257ce4e - https://github.com/jellyfin/jellyfin/releases/tag/v12.0 - https://github.com/jellyfin/jellyfin/blob/v10.11.11/Jellyfin.Api/Controllers/LibraryStructureController.cs#L127-L176 - https://github.com/jellyfin/jellyfin/blob/v10.11.11/Emby.Server.Implementations/Library/LibraryManager.cs#L3255-L3275 - https://www.vulncheck.com/advisories/jellyfin-before-12.0-path-traversal-via-library-virtualfolders-endpoints Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126499 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126499.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- jellyfin jellyfin
fixed in 12.0
Evidence 8
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 5
- Patch
- Repository
- Repository
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126499
Is CVE-2026-126499 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
Before the startup setup wizard is completed, the library virtual folder endpoints accept unauthenticated path traversal requests. These can recursively delete or relocate directories the server can write, including the data directory and jellyfin.db, causing permanent data loss and denial of service.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-126499?
jellyfin: before 12.0.Source: cve.now feed data
Am I affected, and how do I check?
Jellyfin versions before 12.0 are affected, but only while the startup setup wizard has not been completed. Check the installed Jellyfin version and whether the setup wizard has been finished on that server.Source: github.com, vulncheck.com
How do I fix CVE-2026-126499?
Upgrade to Jellyfin 12.0 or later, which contains the fix. Until upgrading, complete the setup wizard immediately after installation and keep a new server off untrusted networks until then.Source: github.com, vulncheck.com