Vendor
LemmyNet
12 known vulnerabilities.
Products
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Medium 6.5
Lemmy: Rate limit bypass via X-Forwarded-For header spoofing in actix-web ConnectionInfo
Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-beta.1, actix-web ConnectionInfo::realip_remote_addr reads the first value of X-Forwarded-For as the client address used by raw_ip_key in crates/utils/src/rate_limit/mod.rs. Le…
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Medium 6.4
Lemmy: Stored XSS via markdown image alt-text in lemmy-ui html5-embed
Lemmy is a link aggregator and forum for the fediverse. Prior to lemmy-ui 0.19.19-beta.1, LemmyNet/lemmy-ui renders Markdown in src/shared/markdown.ts for post bodies, comment bodies, private messages, and community and site sidebars through mdToHtml, which r…
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Medium 6.9
Lemmy: Login Endpoint User Enumeration via HTTP Response Code Differential
Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-beta.1, Lemmy's login endpoint in crates/api/api/src/local_user/login.rs returns different errors depending on whether the username_or_email value exists. LocalUserView::find_b…
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Medium 6.5
Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators
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 LocalU…
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Medium 5.3
Lemmy: Blocked users can edit private messages sent before the block
Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, Lemmy blocks new private messages from a sender after the recipient blocks that sender, but the edit path skips the same block check. create_private_message checks th…
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Medium 5.1
Lemmy: `CollectionAdd::Featured` does not check the post is in the community
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 CollectionTy…
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Medium 6.3
Lemmy: SSRF in /api/v3/post via Webmention dispatch
Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy allows an authenticated low-privileged user to create a link post through POST /api/v3/post. When a post is created in a public community, the backend asynchronously sends…
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Medium 6.5
Lemmy: SSRF and internal image disclosure in post link metadata via unvalidated og:image
Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy fetches metadata for user-supplied post URLs and, under the default StoreLinkPreviews image mode, downloads the preview image through local pict-rs. While the top-level pa…
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Medium 6.5CVE-2026-33693 Public exploit
Lemmy's Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()
Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlli…
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Medium 4.0
Server-Side Request Forgery (SSRF) in activitypub_federation
Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. This vulnerability, which is present in versions 0.6.2 and prior of …