CVE-2026-54738

{"id": "CVE-2026-54738", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-54738", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-21T21:09:45.793083Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 2.5, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "LemmyNet", "product": "lemmy", "versions": [{"status": "affected", "version": "< 0.19.19"}, {"status": "affected", "version": ">= 1.0.0-alpha.5, < 1.0.0-beta.1"}]}]}], "published": "2026-08-19T21:16:58.073", "references": [{"url": "https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/pull/6574", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/pull/6575", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/releases/tag/0.19.19", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1", "source": "security-advisories@github.com"}, {"url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg", "source": "security-advisories@github.com"}, {"url": "https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19", "source": "security-advisories@github.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-799"}]}], "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."}], "lastModified": "2026-09-09T21:15:59.613", "sourceIdentifier": "security-advisories@github.com"}