CVE-2026-54738
MEDIUMDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 36% of all known CVEs.
References
Related Vulnerabilities
Other CWE-799 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-35621 | High | 7.5 | 2.3% | - | - |
| CVE-2016-6543 | Medium | 5.9 | 2.2% | - | - |
| CVE-2021-37910 | Low | 3.7 | 2.1% | - | Fix |
| CVE-2021-32705 | Medium | 5.3 | 1.7% | - | Fix |
| CVE-2021-41177 | High | 8.1 | 1.6% | - | Fix |
| CVE-2021-32703 | Medium | 5.3 | 1.5% | - | Fix |
Common questions
How do I fix CVE-2026-54738?
No published fix for CVE-2026-54738 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-54738 being actively exploited?
Not that we know of. CVE-2026-54738 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.43% is the estimated probability that it will be exploited in the next 30 days. That is higher than 36% of all scored CVEs.
How severe is CVE-2026-54738?
CVE-2026-54738 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-21.