{"cve":{"cve_id":"CVE-2021-40524","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.04386,"epss_percentile":0.90037,"epss_as_of":"2026-06-23","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.)","published_at":"2021-09-05T18:26:26Z","last_modified_at":null,"cvss_v3_score":null,"cvss_v3_vector":null,"cvss_v3_severity":null,"cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":null,"nvd_references":["https://github.com/jedisct1/pure-ftpd/pull/158","https://github.com/jedisct1/pure-ftpd/compare/1.0.49...1.0.50","https://github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:16:09.007548Z"},"effective_severity":null,"badges":["poc"],"impact_analysis":[],"cvss_v3_decoded":{"version":null,"metrics":[]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[],"exploit_refs":[{"source":"nuclei","kind":"nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/network/cves/2021/CVE-2021-40524.yaml","title":"Pure-FTPd 1.0.23 < 1.0.50 - Arbitrary File Upload","author":"pussycat0x","disclosed_at":null}],"news":[],"references":[{"url":"https://github.com/jedisct1/pure-ftpd/pull/158","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/jedisct1/pure-ftpd/compare/1.0.49...1.0.50","source_type":"MISC","tags":[]},{"url":"https://github.com/jedisct1/pure-ftpd/commit/37ad222868e52271905b94afea4fc780d83294b4","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2021-09-05T18:26:26Z","label":"CVE published","source":null},{"type":"poc_available","at":"2026-06-24T00:29:48.638073Z","label":"Public PoC available","source":"nuclei"}]}