Description

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.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  6.5 MEDIUM

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

CNA:  GitHub, Inc.

Base Score:  7.5 HIGH

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

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink	Resource
https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5	Patch
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
NVD-CWE-noinfo	Insufficient Information	NIST
CWE-285	Improper Authorization	GitHub, Inc.
CWE-200	Exposure of Sensitive Information to an Unauthorized Actor	GitHub, Inc.

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Change History

3 change records found show changes

CVE Modified by GitHub, Inc. 5/14/2024 11:00:08 AM

Action	Type	Old Value	New Value

Initial Analysis by NIST 2/02/2024 10:46:30 AM

Action	Type	Old Value	New Value
Added	CPE Configuration		OR *cpe:2.3:a:join-lemmy:lemmy:*:*:*:*:*:rust:*:* versions from (including) 0.17.0 up to (excluding) 0.19.1
Added	CVSS V3.1		NIST AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Added	CWE		NIST NVD-CWE-noinfo
Changed	Reference Type	https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5 No Types Assigned	https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5 Patch
Changed	Reference Type	https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv No Types Assigned	https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv Vendor Advisory

New CVE Received by NIST 1/24/2024 1:15:09 PM

Action	Type	Old Value	New Value
Added	CVSS V3.1		GitHub, Inc. AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Added	CWE		GitHub, Inc. CWE-200
Added	CWE		GitHub, Inc. CWE-285
Added	Description		Record truncated, showing 500 of 1741 characters. View Entire Change Record 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 remo
Added	Reference		GitHub, Inc. https://github.com/LemmyNet/lemmy/commit/bc32b408b523b9b64aa57b8e47748f96cce0dae5 [No types assigned]
Added	Reference		GitHub, Inc. https://github.com/LemmyNet/lemmy/security/advisories/GHSA-r64r-5h43-26qv [No types assigned]