{"attribution":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","cve":{"id":"CVE-2021-27862","sourceIdentifier":"cret@cert.org","published":"2022-09-27T19:15:09.403","lastModified":"2026-06-17T03:45:32.623","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length and Ethernet to Wifi frame conversion (and optionally VLAN0 headers)."},{"lang":"es","value":"Las capacidades de filtrado de red de capa 2, como la protección RA de IPv6, pueden omitirse usando encabezados LLC/SNAP con una longitud no válida y la conversión de tramas de Ethernet a Wifi (y, opcionalmente, encabezados VLAN0)"}],"affected":[{"source":"cret@cert.org","affectedData":[{"vendor":"IEEE","product":"802.2","versions":[{"version":"802.2h-1997","lessThanOrEqual":"802.2h-1997","versionType":"custom","status":"affected"}]},{"vendor":"IETF","product":"draft-ietf-v6ops-ra-guard-08","versions":[{"version":"08","lessThanOrEqual":"08","versionType":"custom","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","baseScore":4.7,"baseSeverity":"MEDIUM","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":2.8,"impactScore":1.4},{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","baseScore":4.7,"baseSeverity":"MEDIUM","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":2.8,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2025-05-21T15:04:33.466068Z","id":"CVE-2021-27862","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"cret@cert.org","type":"Secondary","description":[{"lang":"en","value":"CWE-130"},{"lang":"en","value":"CWE-290"}]},{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-290"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:ieee:ieee_802.2:*:*:*:*:*:*:*:*","versionEndIncluding":"802.2h-1997","matchCriteriaId":"D5B0DDC2-21C5-4682-9AA2-055BF7C722DA"}]}]},{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:ietf:p802.1q:*:*:*:*:*:*:*:*","versionEndIncluding":"d1.0","matchCriteriaId":"94105D2E-950F-4290-8840-301FA908BC8C"}]}]}],"references":[{"url":"https://blog.champtar.fr/VLAN0_LLC_SNAP/","source":"cret@cert.org"},{"url":"https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/","source":"cret@cert.org","tags":["Vendor Advisory"]},{"url":"https://kb.cert.org/vuls/id/855201","source":"cret@cert.org"},{"url":"https://standards.ieee.org/ieee/802.2/1048/","source":"cret@cert.org","tags":["Vendor Advisory"]},{"url":"https://blog.champtar.fr/VLAN0_LLC_SNAP/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Vendor Advisory"]},{"url":"https://kb.cert.org/vuls/id/855201","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://standards.ieee.org/ieee/802.2/1048/","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Vendor Advisory"]},{"url":"https://www.kb.cert.org/vuls/id/855201","source":"af854a3a-2127-422b-91ae-364da2661108"}]}}