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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-54740 Detail

Description

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::is_higher_mod_or_admin_check to enforce moderator rank, but CollectionRemove::verify in crates/apub/activities/src/community/collection_remove.rs only calls verify_mod_action. CollectionRemove::receive dereferences self.object as an ApubPerson, creates a CommunityModeratorForm, and calls CommunityActions::leave without checking that the actor outranks the moderator identified by the object field. In communities with federated moderators, a junior moderator can therefore strip senior moderators from the community moderator list even though the local API rejects the same action. This issue is fixed in versions 0.19.19 and 1.0.0-alpha.18.


Metrics

 
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 CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/LemmyNet/lemmy/commit/d127e714a66f34f6b9c8ea15f20097ac907cdf28 GitHub, Inc.
https://github.com/LemmyNet/lemmy/commit/ede1d348344ca2027fd1bc6a0cab25575c0c3a4c GitHub, Inc.
https://github.com/LemmyNet/lemmy/pull/6475 GitHub, Inc.
https://github.com/LemmyNet/lemmy/pull/6478 GitHub, Inc.
https://github.com/LemmyNet/lemmy/releases/tag/0.19.19 GitHub, Inc.
https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-alpha.18 GitHub, Inc.
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-xmpx-2j2f-c7g7 GitHub, Inc.
https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-862 Missing Authorization GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-54740
NVD Published Date:
08/19/2026
NVD Last Modified:
08/19/2026
Source:
GitHub, Inc.