{"api_version":"1","generated_at":"2026-08-22T19:07:39+00:00","cve":"CVE-2026-54738","urls":{"html":"https://cve.report/CVE-2026-54738","api":"https://cve.report/api/cve/CVE-2026-54738.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-54738","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-54738"},"summary":{"title":"Lemmy: Rate limit bypass via X-Forwarded-For header spoofing in actix-web ConnectionInfo","description":"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.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-08-19 21:16:58","updated_at":"2026-08-21 22:16:40"},"problem_types":["CWE-799","CWE-799 CWE-799: Improper Control of Interaction Frequency"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"LOW"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"6.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","data":{"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":[{"url":"https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19","name":"https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg","name":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/pull/6574","name":"https://github.com/LemmyNet/lemmy/pull/6574","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1","name":"https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82","name":"https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/pull/6575","name":"https://github.com/LemmyNet/lemmy/pull/6575","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.19","name":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.19","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c","name":"https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-54738","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54738","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"LemmyNet","product":"lemmy","version":"affected < 0.19.19","platforms":[]},{"source":"CNA","vendor":"LemmyNet","product":"lemmy","version":"affected >= 1.0.0-alpha.5, < 1.0.0-beta.1","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"54738","cve":"CVE-2026-54738","epss":"0.004280000","percentile":"0.359690000","score_date":"2026-08-21","updated_at":"2026-08-22 00:12:48"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-54738","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-08-21T21:09:45.793083Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-08-21T21:48:26.962Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"lemmy","vendor":"LemmyNet","versions":[{"status":"affected","version":"< 0.19.19"},{"status":"affected","version":">= 1.0.0-alpha.5, < 1.0.0-beta.1"}]}],"descriptions":[{"lang":"en","value":"Lemmy is a link aggregator and forum for the fediverse. 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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.","Type":"Description","Title":"Lemmy: Rate limit bypass via X-Forwarded-For header spoofing in "}]}}}