---
id: CVE-2026-54738
title: Lemmy is a link aggregator and forum for the fediverse
summary: >-
  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…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'
cwe:
  - CWE-799
published: '2026-08-19'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:15:59.613'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54738'
references:
  - url: >-
      https://github.com/LemmyNet/lemmy/commit/41513c89ceecee719bff05acfe613e3b1e85f23c
    label: security-advisories@github.com
  - url: >-
      https://github.com/LemmyNet/lemmy/commit/8b5b2aa78417b53ff3622c01f5bed2f1590f3b82
    label: security-advisories@github.com
  - url: 'https://github.com/LemmyNet/lemmy/pull/6574'
    label: security-advisories@github.com
  - url: 'https://github.com/LemmyNet/lemmy/pull/6575'
    label: security-advisories@github.com
  - url: 'https://github.com/LemmyNet/lemmy/releases/tag/0.19.19'
    label: security-advisories@github.com
  - url: 'https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1'
    label: security-advisories@github.com
  - url: 'https://github.com/LemmyNet/lemmy/security/advisories/GHSA-2hrg-7x4g-9vpg'
    label: security-advisories@github.com
  - url: 'https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19'
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00559
epssPercentile: 0.44199
ingestedAt: '2026-09-09T21:22:45.544Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.