CVE-2021-40524 : In Pure-FTPd before 1.0.50, an incorrect max

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.)

Published 2021-09-05 19:15:15

Updated 2021-11-26 19:49:28

Source MITRE

View at NVD, CVE.org

Vulnerability category: Denial of service

Products affected by CVE-2021-40524

Pureftpd » Pure-ftpd
Versions from including (>=) 1.0.23 and before (<) 1.0.50
cpe:2.3:a:pureftpd:pure-ftpd:*:*:*:*:*:*:*:*
Matching versions

Threat overview for CVE-2021-40524

Top countries where our scanners detected CVE-2021-40524

Top open port discovered on systems with this issue 21

IPs affected by CVE-2021-40524 686

Threat actors abusing to this issue? Yes

Find out if you^* are affected by CVE-2021-40524!

^*Directly or indirectly through your vendors, service providers and 3rd parties. Powered by attack surface intelligence from SecurityScorecard.

Exploit prediction scoring system (EPSS) score for CVE-2021-40524

EPSS FAQ

0.23%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 60 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-40524

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
5.0	MEDIUM	AV:N/AC:L/Au:N/C:N/I:N/A:P	10.0	2.9	NIST
Access Vector: Network Access Complexity: Low Authentication: None Confidentiality Impact: None Integrity Impact: None Availability Impact: Partial
7.5	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	3.9	3.6	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: None User Interaction: None Scope: Unchanged Confidentiality: None Integrity: None Availability: High

CWE ids for CVE-2021-40524

CWE-434 Unrestricted Upload of File with Dangerous Type

The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2021-40524

https://github.com/jedisct1/pure-ftpd/compare/1.0.49...1.0.50

Comparing 1.0.49...1.0.50 · jedisct1/pure-ftpd · GitHub
Patch;Third Party Advisory
https://github.com/jedisct1/pure-ftpd/pull/158

fix the maxfile_size checking bug by DroidTest · Pull Request #158 · jedisct1/pure-ftpd · GitHub
Exploit;Third Party Advisory
https://github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4

Initialize the max upload file size when quotas are enabled · jedisct1/pure-ftpd@37ad222 · GitHub
Patch;Third Party Advisory