{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47223 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47223 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. 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-2021-47223 and fix it if it is affected.\n\nWhat it is: CVE-2021-47223 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. 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-2021-47223 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2021-47223/ (Markdown: https://insights.sbomify.com/CVE-2021-47223/index.md)","id":"CVE-2021-47223","markdown":"https://insights.sbomify.com/CVE-2021-47223/index.md","name":"CVE-2021-47223","record":{"aliases":["DEBIAN-CVE-2021-47223","GHSA-8q2m-46mc-pjw4","UBUNTU-CVE-2021-47223"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A null pointer dereference in the Linux kernel bridge VLAN tunnel egress path allows attackers to cause a denial of service.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix vlan tunnel dst null pointer dereference\n\nThis patch fixes a tunnel_dst null pointer dereference due to lockless\naccess in the tunnel egress path. When deleting a vlan tunnel the\ntunnel_dst pointer is set to NULL without waiting a grace period (i.e.\nwhile it's still usable) and packets egressing are dereferencing it\nwithout checking. Use READ/WRITE_ONCE to annotate the lockless use of\ntunnel_id, use RCU for accessing tunnel_dst and make sure it is read\nonly once and checked in the egress path. The dst is already properly RCU\nprotected so we don't need to do anything fancy than to make sure\ntunnel_id and tunnel_dst are read only once and checked in the egress path.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"net: bridge: fix vlan tunnel dst null pointer dereference","id":"CVE-2021-47223","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2021"},"n_packages":0,"n_references":6,"next":{"headline":"net: ll_temac: Make sure to free skb when it is completely used","id":"CVE-2021-47224"},"packages":[],"prev":{"headline":"net: bridge: fix vlan tunnel dst refcnt when egressing","id":"CVE-2021-47222"},"products":["Linux"],"published":"2024-05-21","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"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":"2026-05-11","vendors":["Linux"]},"summary":"A null pointer dereference in the Linux kernel bridge VLAN tunnel egress path allows attackers to cause a denial of service.","url":"https://insights.sbomify.com/CVE-2021-47223/"}