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pure-ftpd — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-40524

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.)

Products
pure-ftpd
Affected versions
Not specified
Fixed versions
1.0.50-1
CVEs
CVE-2021-40524
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 23:57 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-40524

core-osv · Original source

Published 5 Sept 2021, 19:15 UTC

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.)

osv:DEBIAN-CVE-2021-40524

pure-ftpd

Fixed versions: 1.0.50-1

pure-ftpd

Fixed versions: 1.0.50-1

Complete source record
{
  "id": "8dffeffad664496ebd8f28eb3f4c604cc5b2c3bbf1d77005bea13b0e7d692af5",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-40524",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-40524",
    "summary": "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.)",
    "evidence": "osv:DEBIAN-CVE-2021-40524",
    "products": [
      {
        "name": {
          "value": "pure-ftpd",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.0.50-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "pure-ftpd",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.0.50-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-40524",
      "aliases": [
        "DEBIAN-CVE-2021-40524"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.0.50-1"
                }
              ]
            }
          ],
          "package": {
            "name": "pure-ftpd",
            "purl": "pkg:deb/debian/pure-ftpd?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-40524.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.0.50-1"
                }
              ]
            }
          ],
          "package": {
            "name": "pure-ftpd",
            "purl": "pkg:deb/debian/pure-ftpd?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-40524.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:02:30.745170160Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-40524"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-40524"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-40524",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 419574,
  "published_at": "2021-09-05T19:15:15.08+00:00"
}