CVE-2026-54738
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.5
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
- EPSS probability
- 0.43%
- CWE
- CWE-799
- Published
- 2026-08-19
- Last modified
- 2026-08-21
Affected products
- LemmyNet lemmy
- LemmyNet lemmy
Weakness type
Related vulnerabilities
- CVE-2026-85586 — phpMyFAQ before 4.1.8 CAPTCHA Bypass via store parameter
- CVE-2026-75773 — karakeep-app karakeep Login Endpoint auth.ts authorize excessive authentication
- CVE-2026-19898 — VictoriaMetrics VMAuth Authentication Endpoint main.go requestHandler excessive authentication
- CVE-2026-19897 — mangroup dtale Login Endpoint auth.py login excessive authentication
- CVE-2026-19895 — opensourcepos Open Source Point of Sale Login Endpoint Filters.php index excessive authentication
- CVE-2024-23565 — HCL Aftermarket EPC is vulnerable to email flooding as the application does not have a proper mail...
- CVE-2026-33434 — Wazuh: Rate Limit Bypass via /events Endpoint
- CVE-2026-5233 — Missing Rate Limiting in Mia Technologies' Pizzy Library