CVE-2025-67853: Moodle: moodle: brute-force facilitation due to missing rate limiting in confirmation email service

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-03 · updated 2026-06-17
Weakness: CWE-307

Description

A flaw was found in Moodle. A remote attacker could exploit a lack of proper rate limiting in the confirmation email service. This vulnerability allows attackers to more easily enumerate or guess user credentials, facilitating brute-force attacks against user accounts.

Affected products

Moodle: before 4.1.22; from 4.4.0 before 4.4.11; from 4.5.0 before 4.5.8; from 5.0.0 before 5.0.4; 5.1.0 — fixed in 4.1.22, 4.4.11, 4.5.8, 5.0.4

How to fix

Upgrade to a fixed version: Moodle 4.1.22, 4.4.11, 4.5.8, 5.0.4. Check the vendor advisory for mitigations.

References

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