CVE-2026-54738
Lemmy is a link aggregator and forum for the fediverse.
Impact
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. Lemmy's bundled docker/nginx.conf uses $proxy_add_x_forwarded_for instead of $remote_addr, which appends the real client address to an X-Forwarded-For value supplied by the client. An unauthenticated attacker can therefore place a different spoofed address first on each request and receive a new rate-limit bucket, bypassing limits on POST /api/v4/account/auth/register, POST /api/v4/account/auth/login, POST /api/v4/post, POST /api/v4/comment, GET /api/v4/search, POST /api/v4/image, and POST /api/v4/account/import_settings. This permits excessive account creation, brute-force attempts, spam, scraping, uploads, and repeated imports. This issue is fixed in versions 0.19.19 and 1.0.0-beta.1.
Affected products
| Product | Affected versions |
|---|---|
| Lemmy Is A Link Aggregator And Forum For The Fediverse. | before 0.19.19 |
Versions were read from the advisory text. No structured product data has been published for this record yet.
Weakness classification
References
- NVD record
- CVE.org record
- https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c
- https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82
- https://github.com/LemmyNet/lemmy/pull/6574
- https://github.com/LemmyNet/lemmy/pull/6575
- https://github.com/LemmyNet/lemmy/releases/tag/0.19.19
- https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1
- https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg
- https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19