{"answers":{"affected":"It affects 2 products.","exploited":"There is no known exploitation of CVE-2021-27854 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-27854 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-27854 is a medium-severity vulnerability in IEEE 802.2, published on 27 Sep 2022. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-27854 and fix it if it is affected.\n\nWhat it is: CVE-2021-27854 is a medium-severity vulnerability in IEEE 802.2, published on 27 Sep 2022. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-27854 in the wild and no public exploit code.\n\nAffected product: IEEE 802.2. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-27854/ (Markdown: https://insights.sbomify.com/CVE-2021-27854/index.md)","id":"CVE-2021-27854","markdown":"https://insights.sbomify.com/CVE-2021-27854/index.md","name":"CVE-2021-27854","record":{"aliases":["GHSA-433g-q37h-7crr"],"analysis":{"component_type":"network_device","fix_type":"no_fix_stated","impacts":["security_bypass"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Network protocol standards","requires_auth":"none","summary":"Attackers can bypass Layer 2 network filtering mechanisms like IPv6 RA guard by manipulating VLAN and LLC/SNAP headers during frame translation.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"certcc","cpe":[{"product":"ieee_802.2","vendor":"ieee"},{"product":"p802.1q","vendor":"ietf"}],"cvss":{"score":4.7,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-290","name":"Authentication Bypass by Spoofing"}],"description":"Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"L2 network filtering bypass using stacked VLAN0, LLC/SNAP headers, and Ethernet to Wifi frame translation","id":"CVE-2021-27854","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"security_feature_bypass","year":"2021"},"n_packages":0,"n_references":5,"next":{"headline":"FatPipe software allows privilege escalation","id":"CVE-2021-27855"},"packages":[],"prev":{"headline":"L2 network filtering can be bypassed using stacked VLAN0 and LLC/SNAP headers","id":"CVE-2021-27853"},"products":["802.2","P802.1Q","draft-ietf-v6ops-ra-guard"],"published":"2022-09-27","related":[{"cvss_score":4.7,"headline":"L2 network filtering bypass using stacked VLAN0 and LLC/SNAP headers with invalid lengths","id":"CVE-2021-27861","kev_date_added":null,"published":"2022-09-27"},{"cvss_score":4.7,"headline":"Security feature bypass in 802.2","id":"CVE-2021-27862","kev_date_added":null,"published":"2022-09-27"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2025-11-04","vendors":["IEEE","IETF"]},"summary":"Attackers can bypass Layer 2 network filtering mechanisms like IPv6 RA guard by manipulating VLAN and LLC/SNAP headers during frame translation.","url":"https://insights.sbomify.com/CVE-2021-27854/"}