CVE-2021-40524: Pureftpd Pure-Ftpd

High severity, CVSS 7.5. EPSS: 4.3% chance of exploitation in the next 30 days.

In Pure-FTPd before 1.0.50, an incorrect max_filesize quota mechanism in the server allows attackers to upload files of unbounded size, which may lead to denial of service or a server hang. This occurs because a certain greater-than-zero test does not anticipate an initial -1 value. (Versions 1.0.23 through 1.0.49 are affected.)

Affected products

• Pureftpd Pure-Ftpd: from 1.0.23, before 1.0.50 (fixed in 1.0.50)

Published 2021-09-05. Last modified 2026-06-17.