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VulnerabilityPublished

Lemmy api: Lemmy resend-verification endpoint exposes registered email addresses to unauthenticated users

Affects lemmy_apiSource GCVE Database

0

Public exploit available · CVSS 6.9 Medium.

Data as of 27 Oct 2026, 02:27 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
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/E:P

What to do

Affected software

ProductAffectedFixed in
crates.iolemmy_apiAffected
  • <=0.19.1-rc.1
Fixed in–

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AI-suggested

A fix is available by adopting the password-reset endpoint's pattern: move the lookup and email sending into a helper function, ignore errors in the handler, and always return a generic success response for syntactically valid input. This prevents account enumeration.

Description

The Lemmy API's resend-verification endpoint allows unauthenticated users to distinguish between registered and unregistered email addresses by returning different responses. This enables malicious actors to enumerate registered email addresses without authentication. The endpoint lacks endpoint-specific rate limiting for enumeration, increasing the risk of automated probing. The issue affects versions up to and including 0.19.1-rc.1.

References

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