{"api_version":"1","generated_at":"2026-04-22T22:49:45+00:00","cve":"CVE-2021-20235","urls":{"html":"https://cve.report/CVE-2021-20235","api":"https://cve.report/api/cve/CVE-2021-20235.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-20235","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-20235"},"summary":{"title":"CVE-2021-20235","description":"There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. 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A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality."}]}},"nvd":{"publishedDate":"2021-04-01 14:15:00","lastModifiedDate":"2023-11-07 03:29:00","problem_types":["CWE-787"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH"},"exploitabilityScore":2.2,"impactScore":5.9},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:N/C:P/I:P/A:P","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"PARTIAL","availabilityImpact":"PARTIAL","baseScore":6.8},"severity":"MEDIUM","exploitabilityScore":8.6,"impactScore":6.4,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:zeromq:libzmq:*:*:*:*:*:*:*:*","versionStartIncluding":"4.2.0","versionEndExcluding":"4.3.3","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"20235","Ordinal":"194276","Title":"CVE-2021-20235","CVE":"CVE-2021-20235","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"20235","Ordinal":"1","NoteData":"There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"20235","Ordinal":"2","NoteData":"2021-04-01","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"20235","Ordinal":"3","NoteData":"2021-04-01","Type":"Other","Title":"Modified"}]}}}