---
cve: "CVE-2026-54738"
severity: "MEDIUM"
cvss: 6.5
epss: "43%"
vendor: "LemmyNet"
kev: false
exploited: false
published: "2026-08-19 20:27:45"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:26:52+02:00"
---

# CVE-2026-54738

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- f6e986e7e54d456aa1ffec38f1576c5bb15e0afd (Commit)
- fe8b39b10bb70e9c0edca2df7a63c8f8d4059c98 (Commit)

## Referenzen

- <https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg>
- <https://github.com/LemmyNet/lemmy/pull/6574>
- <https://github.com/LemmyNet/lemmy/pull/6575>
- <https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c>
- <https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82>
- <https://github.com/LemmyNet/lemmy/releases/tag/0.19.19>
- <https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1>
- <https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-54738) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_