{"cve":{"cve_id":"CVE-2021-28816","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":0.00898,"epss_percentile":0.54927,"epss_as_of":"2026-06-23","description":"A stack buffer overflow vulnerability has been reported to affect QNAP device running QTS, QuTScloud, QuTS hero. If exploited, this vulnerability allows attackers to execute arbitrary code. We have already fixed this vulnerability in the following versions of QTS, QuTScloud, QuTS hero: QTS 4.5.4.1715 build 20210630 and later QTS 5.0.0.1716 build 20210701 and later QTS 4.3.3.1693 build 20210624 and later QTS 4.3.6.1750 build 20210730 and later QuTScloud c4.5.6.1755 and later QuTS hero h4.5.4.1771 build 20210825 and later","published_at":"2021-09-10T04:00:21.577000Z","last_modified_at":null,"cvss_v3_score":7.6,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H","cvss_v3_severity":"HIGH","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":["CWE-787"],"nvd_references":["https://www.qnap.com/en/security-advisory/qsa-21-33"],"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":"2026-06-28T23:15:26.101164Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"L","value_label":"Low"},{"metric":"I","name":"Integrity","value":"L","value_label":"Low"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"qts","product_name":"QTS","version_start":"unspecified","version_start_inclusive":true,"version_end":"4.5.4.1715 build 20210630","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:qts:unspecified:4.5.4.1715 build 20210630"},{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"qts","product_name":"QTS","version_start":"unspecified","version_start_inclusive":true,"version_end":"5.0.0.1716 build 20210701","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:qts:unspecified:5.0.0.1716 build 20210701"},{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"qts","product_name":"QTS","version_start":"unspecified","version_start_inclusive":true,"version_end":"4.3.3.1693 build 20210624","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:qts:unspecified:4.3.3.1693 build 20210624"},{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"qts","product_name":"QTS","version_start":"unspecified","version_start_inclusive":true,"version_end":"4.3.6.1750 build 20210730","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:qts:unspecified:4.3.6.1750 build 20210730"},{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"qutscloud","product_name":"QuTScloud","version_start":"unspecified","version_start_inclusive":true,"version_end":"c4.5.6.1755","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:qutscloud:unspecified:c4.5.6.1755"},{"vendor_slug":"qnap-systems-inc.","vendor_name":"QNAP Systems Inc.","product_slug":"quts-hero","product_name":"QuTS hero","version_start":"unspecified","version_start_inclusive":true,"version_end":"h4.5.4.1771 build 20210825","version_end_inclusive":false,"cpe23_uri":"cve5:qnap-systems-inc.:quts-hero:unspecified:h4.5.4.1771 build 20210825"}],"exploit_refs":[],"news":[],"references":[{"url":"https://www.qnap.com/en/security-advisory/qsa-21-33","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2021-09-10T04:00:21.577000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:18:04.076611Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:18:04.076611Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:18:04.076611Z","label":"CVSS score revised","source":"cvelistv5"}]}