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.)

References

Affected packages

Git / github.com/jedisct1/pure-ftpd

Affected ranges

Type

GIT

Repo

https://github.com/jedisct1/pure-ftpd

Events

Introduced

Fixed

868f0e2277e3f5890ca08c84d41de8065a7d8bc3

Fixed

37ad222868e52271905b94afea4fc780d83294b4

Database specific

{
    "extracted_events": [
        {
            "introduced": "1.0.23"
        },
        {
            "fixed": "1.0.50"
        }
    ],
    "source": [
        "CPE_FIELD",
        "REFERENCES"
    ],
    "cpe": "cpe:2.3:a:pureftpd:pure-ftpd:*:*:*:*:*:*:*:*"
}

Affected versions

1.*

1.0.33

1.0.34

1.0.35

1.0.36

1.0.37

1.0.38

1.0.39

1.0.40

1.0.41

1.0.43

1.0.44

1.0.45

1.0.48

1.0.49

Database specific

vanir_signatures

[
    {
        "signature_version": "v1",
        "deprecated": false,
        "source": "https://github.com/jedisct1/pure-ftpd/commit/868f0e2277e3f5890ca08c84d41de8065a7d8bc3",
        "digest": {
            "line_hashes": [
                "62861421324718626283205813091113225033",
                "276556215880805753523756337752274567287",
                "139825961526930270406704652117385392827"
            ],
            "threshold": 0.9
        },
        "target": {
            "file": "src/simpleconf_ftpd.h"
        },
        "signature_type": "Line",
        "id": "CVE-2021-40524-00e4d04c"
    },
    {
        "signature_version": "v1",
        "deprecated": false,
        "source": "https://github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4",
        "digest": {
            "line_hashes": [
                "143088216645301880473965997968294163065",
                "268607288337989793077162423436249802443",
                "280366719401112403696117270706084821257",
                "25497428101258363206954973861780601325",
                "122625483517188019176324232254541051564"
            ],
            "threshold": 0.9
        },
        "target": {
            "file": "src/ftpd.c"
        },
        "signature_type": "Line",
        "id": "CVE-2021-40524-178db787"
    },
    {
        "signature_version": "v1",
        "deprecated": false,
        "source": "https://github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4",
        "digest": {
            "function_hash": "310052781692296683813829170466513134176",
            "length": 5664.0
        },
        "target": {
            "file": "src/ftpd.c",
            "function": "dostor"
        },
        "signature_type": "Function",
        "id": "CVE-2021-40524-1865d9b9"
    }
]

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-40524.json"

vanir_signatures_modified

"2026-04-12T01:58:53Z"