File Browser’s insecure JWT handling can lead to session replay attacks after logout

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-53826: 0.55% estimated exploitation activity in the next 30 days; percentile 46.20 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary File Browser’s authentication system issues long-lived JWT tokens that remain valid even after the user logs out. Please refer to the CWE's listed in this report for further reference and system standards. In summary, the main issue is: - Tokens remain valid after logout (session replay attacks) In this report, I used docker as the documentation instruct: Details Issue: Tokens remain valid after logout (session replay attacks) After logging in and receiving a JWT token, the user can explicitly "log out." However, this action does not invalidate the issued JWT. Any captured token can be replayed post-logout until it expires naturally. The backend does not track active sessions or invalidate existing tokens on logout. Login request: The check found in the code https://github.com/filebrowser/filebrowser/blob/master/http/auth.go is not enough. There is no server-side blacklist or token invalidation on logout. Token renewal and validity only depends on expiry and user store…

Published by the source

16 Jul 2025, 14:09 UTC

Last modified by the source

29 Jul 2025, 23:17 UTC

Source last checked

26 Oct 2026, 15:09 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7xwp-2cpp-p8r7

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# Patch Next advisory brief: CVE-2025-53826

Advisory: File Browser’s insecure JWT handling can lead to session replay attacks after logout
IDs: CVE-2025-53826, GHSA-7xwp-2cpp-p8r7
Record: https://patchnext.com/advisories/cve-2025-53826 (revision 1, source checked 26 Oct 2026, 15:09 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/filebrowser/filebrowser/v2: affected <= 2.39.0
- Go github.com/filebrowser/filebrowser: affected <= 2.39.0

## Suggested inspection (read-only)
- Go github.com/filebrowser/filebrowser/v2: check the installed version with your package manager.
- Go github.com/filebrowser/filebrowser: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/filebrowser/filebrowser/v2, github.com/filebrowser/filebrowser.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7xwp-2cpp-p8r7 (GitHub-reviewed advisory GHSA-7xwp-2cpp-p8r7 lists affected ranges: Go github.com/filebrowser/filebrowser >=0 =0 <=2.39.0)

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