CVE-2026-54742

Published: Ago 19, 2026 Last Modified: Ago 20, 2026

ExploitDB:

Other exploit source:

Google Dorks:

MEDIUM 5,1

Source: [email protected]

Attack Vector: network

Attack Complexity: low

Privileges Required: high

User Interaction: none

Confidentiality: N/A

Integrity: N/A

Availability: N/A

Description

AI Translation Available

Lemmy is a link aggregator and forum for the fediverse. From 0.19.18 until 0.19.19 and 1.0.0-alpha.20, a community moderator can feature or unfeature posts in other communities through federated CollectionAdd and CollectionRemove activities using CollectionType::Featured. After verify_mod_action authorizes the actor against self.community(), the receive handlers in crates/apub/activities/src/community/collection_add.rs and crates/apub/activities/src/community/collection_remove.rs dereference self.object as an ApubPost and update featured_community without verifying that post.community_id equals community.id. A moderator can therefore target an unrelated post owned by another community, push it into featured feeds and listings, or undo another community's legitimate curation decision. This issue is fixed in versions 0.19.19 and 1.0.0-alpha.20.

863

Incorrect Authorization

Incomplete

Abstraction: Class Structure: Simple

Common Consequences

Security Scopes Affected:

Confidentiality Integrity Access Control Availability

Potential Impacts:

Read Application Data Read Files Or Directories Modify Application Data Modify Files Or Directories Gain Privileges Or Assume Identity Bypass Protection Mechanism Execute Unauthorized Code Or Commands Dos: Crash, Exit, Or Restart Dos: Resource Consumption (Cpu) Dos: Resource Consumption (Memory) Dos: Resource Consumption (Other)