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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-54739 Detail

Description

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-beta.1, Lemmy's login endpoint in crates/api/api/src/local_user/login.rs returns different errors depending on whether the username_or_email value exists. LocalUserView::find_by_email_or_name propagates a NotFound response for an unknown account, while an existing account with a wrong password returns LemmyErrorType::IncorrectLogin. This observable response discrepancy, including HTTP 404 for a nonexistent account and HTTP 400 for an incorrect password on an existing account, allows an unauthenticated attacker to confirm registered usernames or email addresses and use the results for targeted credential attacks or social engineering. This issue is fixed in versions 0.19.19 and 1.0.0-beta.1.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 6.9 MEDIUM
Vector:  CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/LemmyNet/lemmy/commit/4d235a1b668b7dda6b73dbbc9ca289bb40acfa83 GitHub, Inc.
https://github.com/LemmyNet/lemmy/commit/59e968a5ac36d36d08a59028e2dbb92641536964 GitHub, Inc.
https://github.com/LemmyNet/lemmy/pull/6531 GitHub, Inc.
https://github.com/LemmyNet/lemmy/pull/6535 GitHub, Inc.
https://github.com/LemmyNet/lemmy/releases/tag/0.19.19 GitHub, Inc.
https://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1 GitHub, Inc.
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-xgg7-8hvq-8m65 GitHub, Inc.
https://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-204 Observable Response Discrepancy GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-54739
NVD Published Date:
08/19/2026
NVD Last Modified:
08/19/2026
Source:
GitHub, Inc.