{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54738","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-06-15T23:07:33.233Z","datePublished":"2026-08-19T20:27:45.162Z","dateUpdated":"2026-08-21T21:48:26.962Z"},"containers":{"cna":{"title":"Lemmy: Rate limit bypass via X-Forwarded-For header spoofing in actix-web ConnectionInfo","problemTypes":[{"descriptions":[{"cweId":"CWE-799","lang":"en","description":"CWE-799: Improper Control of Interaction Frequency","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","version":"3.1"}}],"references":[{"name":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg","tags":["x_refsource_CONFIRM"],"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg"},{"name":"https://github.com/LemmyNet/lemmy/pull/6574","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/pull/6574"},{"name":"https://github.com/LemmyNet/lemmy/pull/6575","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/pull/6575"},{"name":"https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c"},{"name":"https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82"},{"name":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.19","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.19"},{"name":"https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1"},{"name":"https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19","tags":["x_refsource_MISC"],"url":"https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19"}],"affected":[{"vendor":"LemmyNet","product":"lemmy","versions":[{"version":"< 0.19.19","status":"affected"},{"version":">= 1.0.0-alpha.5, < 1.0.0-beta.1","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-19T20:27:45.162Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-2hrg-7x4g-9vpg","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T21:09:45.793083Z","id":"CVE-2026-54738","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-21T21:48:26.962Z"}}]}}