github - ghsa-r64r-5h43-26qv

GHSA-R64R-5H43-26QV

Vulnerability from github – Published: 2024-01-24 21:13 – Updated: 2024-01-24 21:13

Summary

Any authenticated user may obtain private message details from other users on the same instance

Details

Summary

Users can report private messages, even when they're neither sender nor recipient of the message. The API response to creating a private message report contains the private message itself, which means any user can just iterate over message ids to (loudly) obtain all private messages of an instance. A user with instance admin privileges can also abuse this if the private message is removed from the response, as they're able to see the resulting reports.

Details

Creating a private message report by POSTing to /api/v3/private_message/report does not validate whether the reporter is the recipient of the message. At least lemmy-ui does not allow the sender to report the message; the API method should likely be restricted to accessible to recipients only. The API response when creating a report contains the private_message_report_view with all the details of the report, including the private message that has been reported:

Example response In the report below, the creator with id 3 is different from the private message creator (id 2) and private message recipient (id 6).

{
  "private_message_report_view": {
    "private_message_report": {
      "id": 14,
      "creator_id": 3,
      "private_message_id": 7,
      "original_pm_text": "testfoo",
      "reason": "reporting id 7",
      "resolved": false,
      "published": "2023-12-15T19:23:03.441967Z"
    },
    "private_message": {
      "id": 7,
      "creator_id": 2,
      "recipient_id": 6,
      "content": "testfoo",
      "deleted": false,
      "read": false,
      "published": "2023-12-15T19:21:41.920872Z",
      "ap_id": "https://1b1w56.lem.rocks/private_message/7",
      "local": true
    },
    "private_message_creator": {
      "id": 2,
      "name": "admin",
      "banned": false,
      "published": "2023-12-14T23:45:05.055427Z",
      "actor_id": "https://1b1w56.lem.rocks/u/admin",
      "local": true,
      "deleted": false,
      "bot_account": false,
      "instance_id": 1
    },
    "creator": {
      "id": 3,
      "name": "testuser1",
      "banned": false,
      "published": "2023-12-14T23:47:57.571772Z",
      "actor_id": "https://1b1w56.lem.rocks/u/testuser1",
      "local": true,
      "deleted": false,
      "bot_account": false,
      "instance_id": 1
    }
  }
}

If these details were not available in the response, but reports could still be created by any user, or at least by any admin, this would allow an instance admin to create reports and obtain the message contents from the report system.

This was originally discovered from incorrect reports on a 0.18.5 instance and has been replicated in a 0.19.0 test environment.

PoC

curl -v 'https://myinstance.tld/api/v3/private_message/report' -X POST -H 'Content-Type: application/json' -H 'authorization: Bearer ...' --data-raw '{"private_message_id":1,"reason":"i like reports"}'

Impact

Any authenticated user can obtain arbitrary (untargeted) private message contents. Privileges required depend on the instance configuration; when registratons are enabled without application system, the privileges required are practically none. When registration applications are required, privileges required could be considered low, but this assessment heavily varies by instance.

Detection

Any private message reports where the report creator is not equal to the private message recipient may be an attempt to exploit this. As this was originally discovered from an incorrect report, likely related to a bug in a client app, it should be noted that not all mismatching reports should be considered malicious; though a frequent occurrence of them likely indicates an exploitation attempt.

Workaround when updating is not immediately possible

If an update to a fixed Lemmy version is not immediately possible, the API route can be blocked in the reverse proxy. This will prevent anyone from reporting private messages, but it will also prevent exploitation before the update has been applied.

nginx example:

location = /api/v3/private_message/report {
  default_type application/json;
  return 403 '{"error":"couldnt_create_report"}';
}

Severity ?

7.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "lemmy_server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.17.0"
            },
            {
              "fixed": "0.19.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-23649"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-01-24T21:13:39Z",
    "nvd_published_at": "2024-01-24T18:15:09Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nUsers can report private messages, even when they\u0027re neither sender nor recipient of the message.\nThe API response to creating a private message report contains the private message itself, which means any user can just iterate over message ids to (loudly) obtain all private messages of an instance.\nA user with instance admin privileges can also abuse this if the private message is removed from the response, as they\u0027re able to see the resulting reports.\n\n### Details\nCreating a private message report by POSTing to `/api/v3/private_message/report` does not validate whether the reporter is the recipient of the message.\nAt least lemmy-ui does not allow the sender to report the message; the API method should likely be restricted to accessible to recipients only.\nThe API response when creating a report contains the `private_message_report_view` with all the details of the report, including the private message that has been reported:\n\u003cdetails\u003e\n\n\u003csummary\u003eExample response\u003c/summary\u003e\n\nIn the report below, the creator with id 3 is different from the private message creator (id 2) and private message recipient (id 6).\n\n```json\n{\n  \"private_message_report_view\": {\n    \"private_message_report\": {\n      \"id\": 14,\n      \"creator_id\": 3,\n      \"private_message_id\": 7,\n      \"original_pm_text\": \"testfoo\",\n      \"reason\": \"reporting id 7\",\n      \"resolved\": false,\n      \"published\": \"2023-12-15T19:23:03.441967Z\"\n    },\n    \"private_message\": {\n      \"id\": 7,\n      \"creator_id\": 2,\n      \"recipient_id\": 6,\n      \"content\": \"testfoo\",\n      \"deleted\": false,\n      \"read\": false,\n      \"published\": \"2023-12-15T19:21:41.920872Z\",\n      \"ap_id\": \"https://1b1w56.lem.rocks/private_message/7\",\n      \"local\": true\n    },\n    \"private_message_creator\": {\n      \"id\": 2,\n      \"name\": \"admin\",\n      \"banned\": false,\n      \"published\": \"2023-12-14T23:45:05.055427Z\",\n      \"actor_id\": \"https://1b1w56.lem.rocks/u/admin\",\n      \"local\": true,\n      \"deleted\": false,\n      \"bot_account\": false,\n      \"instance_id\": 1\n    },\n    \"creator\": {\n      \"id\": 3,\n      \"name\": \"testuser1\",\n      \"banned\": false,\n      \"published\": \"2023-12-14T23:47:57.571772Z\",\n      \"actor_id\": \"https://1b1w56.lem.rocks/u/testuser1\",\n      \"local\": true,\n      \"deleted\": false,\n      \"bot_account\": false,\n      \"instance_id\": 1\n    }\n  }\n}\n```\n\n\u003c/details\u003e\n\nIf these details were not available in the response, but reports could still be created by any user, or at least by any admin, this would allow an instance admin to create reports and obtain the message contents from the report system.\n\nThis was originally discovered from incorrect reports on a 0.18.5 instance and has been replicated in a 0.19.0 test environment.\n\n### PoC\n\n```bash\ncurl -v \u0027https://myinstance.tld/api/v3/private_message/report\u0027 -X POST -H \u0027Content-Type: application/json\u0027 -H \u0027authorization: Bearer ...\u0027 --data-raw \u0027{\"private_message_id\":1,\"reason\":\"i like reports\"}\u0027\n```\n\n### Impact\nAny authenticated user can obtain arbitrary (untargeted) private message contents.\nPrivileges required depend on the instance configuration; when registratons are enabled without application system, the privileges required are practically none.\nWhen registration applications are required, privileges required could be considered low, but this assessment heavily varies by instance.\n\n### Detection\n\nAny private message reports where the report creator is not equal to the private message recipient may be an attempt to exploit this.\nAs this was originally discovered from an incorrect report, likely related to a bug in a client app, it should be noted that not all mismatching reports should be considered malicious; though a frequent occurrence of them likely indicates an exploitation attempt.\n\n### Workaround when updating is not immediately possible\n\nIf an update to a fixed Lemmy version is not immediately possible, the API route can be blocked in the reverse proxy.\nThis will prevent anyone from reporting private messages, but it will also prevent exploitation before the update has been applied.\n\nnginx example:\n```nginx\nlocation = /api/v3/private_message/report {\n  default_type application/json;\n  return 403 \u0027{\"error\":\"couldnt_create_report\"}\u0027;\n}\n```",
  "id": "GHSA-r64r-5h43-26qv",
  "modified": "2024-01-24T21:13:39Z",
  "published": "2024-01-24T21:13:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-23649"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/LemmyNet/lemmy"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Any authenticated user may obtain private message details from other users on the same instance"
}

CVE-2024-23649 (GCVE-0-2024-23649)

Vulnerability from cvelistv5 – Published: 2024-01-24 18:09 – Updated: 2025-05-30 14:16

Title

Any authenticated user may obtain private message details from other users on the same instance

Summary

Lemmy is a link aggregator and forum for the fediverse. Starting in version 0.17.0 and prior to version 0.19.1, users can report private messages, even when they're neither sender nor recipient of the message. The API response to creating a private message report contains the private message itself, which means any user can just iterate over message ids to (loudly) obtain all private messages of an instance. A user with instance admin privileges can also abuse this if the private message is removed from the response, as they're able to see the resulting reports. Creating a private message report by POSTing to `/api/v3/private_message/report` does not validate whether the reporter is the recipient of the message. lemmy-ui does not allow the sender to report the message; the API method should likely be restricted to accessible to recipients only. The API response when creating a report contains the `private_message_report_view` with all the details of the report, including the private message that has been reported: Any authenticated user can obtain arbitrary (untargeted) private message contents. Privileges required depend on the instance configuration; when registrations are enabled without application system, the privileges required are practically none. When registration applications are required, privileges required could be considered low, but this assessment heavily varies by instance. Version 0.19.1 contains a patch for this issue. A workaround is available. If an update to a fixed Lemmy version is not immediately possible, the API route can be blocked in the reverse proxy. This will prevent anyone from reporting private messages, but it will also prevent exploitation before the update has been applied.

Severity ?

7.5 (High)


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

CWE

CWE-285 - Improper Authorization
CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

Assigner

GitHub_M

References

URL

Tags

	https://github.com/LemmyNet/lemmy/security/adviso…	x_refsource_CONFIRM
	https://github.com/LemmyNet/lemmy/commit/bc32b408…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	LemmyNet	lemmy	Affected: >= 0.17.0, < 0.19.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-01T23:06:25.335Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "name": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv",
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv"
          },
          {
            "name": "https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5",
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2024-23649",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-05-08T15:42:46.679129Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-05-30T14:16:25.819Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "lemmy",
          "vendor": "LemmyNet",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.17.0, \u003c 0.19.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Lemmy is a link aggregator and forum for the fediverse. Starting in version 0.17.0 and prior to version 0.19.1, users can report private messages, even when they\u0027re neither sender nor recipient of the message. The API response to creating a private message report contains the private message itself, which means any user can just iterate over message ids to (loudly) obtain all private messages of an instance. A user with instance admin privileges can also abuse this if the private message is removed from the response, as they\u0027re able to see the resulting reports.\n\nCreating a private message report by POSTing to `/api/v3/private_message/report` does not validate whether the reporter is the recipient of the message. lemmy-ui does not allow the sender to report the message; the API method should likely be restricted to accessible to recipients only. The API response when creating a report contains the `private_message_report_view` with all the details of the report, including the private message that has been reported:\n\nAny authenticated user can obtain arbitrary (untargeted) private message contents. Privileges required depend on the instance configuration; when registrations are enabled without application system, the privileges required are practically none. When registration applications are required, privileges required could be considered low, but this assessment heavily varies by instance.\n\nVersion 0.19.1 contains a patch for this issue. A workaround is available. If an update to a fixed Lemmy version is not immediately possible, the API route can be blocked in the reverse proxy. This will prevent anyone from reporting private messages, but it will also prevent exploitation before the update has been applied."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-285",
              "description": "CWE-285: Improper Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-01-24T18:09:30.401Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv"
        },
        {
          "name": "https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5"
        }
      ],
      "source": {
        "advisory": "GHSA-r64r-5h43-26qv",
        "discovery": "UNKNOWN"
      },
      "title": "Any authenticated user may obtain private message details from other users on the same instance"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2024-23649",
    "datePublished": "2024-01-24T18:09:30.401Z",
    "dateReserved": "2024-01-19T00:18:53.234Z",
    "dateUpdated": "2025-05-30T14:16:25.819Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-R64R-5H43-26QV

Summary

Details

PoC

Impact

Detection

Workaround when updating is not immediately possible

CVE-2024-23649 (GCVE-0-2024-23649)

Tags

Sightings

Nomenclature