{"id":"CVE-2021-0239","state":"PUBLISHED","title":"Junos OS Evolved: Denial of Service due to receipt of specific genuine layer 2 frames.","description":"In Juniper Networks Junos OS Evolved, receipt of a stream of specific genuine Layer 2 frames may cause the Advanced Forwarding Toolkit (AFT) manager process (Evo-aftmand), responsible for handling Route, Class-of-Service (CoS), Firewall operations within the packet forwarding engine (PFE) to crash and restart, leading to a Denial of Service (DoS) condition. By continuously sending this specific stream of genuine Layer 2 frames, an attacker can repeatedly crash the PFE, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R1-EVO. This issue does not affect Junos OS versions.","publishedAt":"2021-04-22T19:37:05.415Z","updatedAt":"2024-09-16T17:49:30.356Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"juniper"},"assigner":"juniper","products":["Juniper Networks Junos OS Evolved"],"affected":[{"vendor":"Juniper Networks","product":"Junos OS Evolved","versions":[{"version":"unspecified","status":"affected","lessThan":"20.4R1-EVO","versionType":"custom"}]}],"references":["https://kb.juniper.net/JSA11134"],"weaknesses":["CWE-754"],"ingestedAt":"2026-10-29T19:47:50.134Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/0xxx/CVE-2021-0239.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2021-0239","state":"PUBLISHED","datePublished":"2021-04-22T19:37:05.415Z","dateUpdated":"2024-09-16T17:49:30.356Z","assignerShortName":"juniper","assignerOrgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","dateReserved":"2020-10-27T00:00:00.000Z"},"containers":{"cna":{"title":"Junos OS Evolved: Denial of Service due to receipt of specific genuine layer 2 frames.","descriptions":[{"lang":"en","value":"In Juniper Networks Junos OS Evolved, receipt of a stream of specific genuine Layer 2 frames may cause the Advanced Forwarding Toolkit (AFT) manager process (Evo-aftmand), responsible for handling Route, Class-of-Service (CoS), Firewall operations within the packet forwarding engine (PFE) to crash and restart, leading to a Denial of Service (DoS) condition. By continuously sending this specific stream of genuine Layer 2 frames, an attacker can repeatedly crash the PFE, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R1-EVO. 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