CVE-2021-40524: pureftpd pure-ftpd
Vulnerability summary
CVE-2021-40524 is a high (CVSS 7.5) vulnerability in pureftpd pure-ftpd. EPSS estimates a 4.29% chance of exploitation in the next 30 days, higher than 91% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 05-09-2021PublishedVulnerability first disclosed.
- 04-11-2025Last modifiedVulnerability information updated.
Description
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.)
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
4.29%
Chance of exploitation in the next 30 days
Percentile
91%
Versus all other CVEs
30-day change
0.00 pp
From 4.29% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundPure Ftpd
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Debian1 product
- pure-ftpd< 1.0.50-1 | < 1.0.49-4.1+deb11u1
Pureftpd1 product
- pure-ftpd≥ 1.0.23, < 1.0.50
Ubuntu1 product
- pure-ftpdAll versions (No fix recorded)
3 vendors · 3 products
References
7 links- github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4X Refsource CONFIRMPatchThird Party Advisory
