{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47394 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47394 is a high-severity use after free 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-2021-47394 and fix it if it is affected.\n\nWhat it is: CVE-2021-47394 is a high-severity use after free 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-2021-47394 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-2021-47394/ (Markdown: https://insights.sbomify.com/CVE-2021-47394/index.md)","id":"CVE-2021-47394","markdown":"https://insights.sbomify.com/CVE-2021-47394/index.md","name":"CVE-2021-47394","record":{"aliases":["DEBIAN-CVE-2021-47394","GHSA-p2qw-28x5-q4gw","UBUNTU-CVE-2021-47394"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free in the Linux kernel netfilter subsystem allows local attackers to potentially execute code or escalate privileges via race conditions.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: unlink table before deleting it\n\nsyzbot reports following UAF:\nBUG: KASAN: use-after-free in memcmp+0x18f/0x1c0 lib/string.c:955\n nla_strcmp+0xf2/0x130 lib/nlattr.c:836\n nft_table_lookup.part.0+0x1a2/0x460 net/netfilter/nf_tables_api.c:570\n nft_table_lookup net/netfilter/nf_tables_api.c:4064 [inline]\n nf_tables_getset+0x1b3/0x860 net/netfilter/nf_tables_api.c:4064\n nfnetlink_rcv_msg+0x659/0x13f0 net/netfilter/nfnetlink.c:285\n netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504\n\nProblem is that all get operations are lockless, so the commit_mutex\nheld by nft_rcv_nl_event() isn't enough to stop a parallel GET request\nfrom doing read-accesses to the table object even after synchronize_rcu().\n\nTo avoid this, unlink the table first and store the table objects in\non-stack scratch space.","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":"netfilter: nf_tables: unlink table before deleting it","id":"CVE-2021-47394","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"mac80211: limit injected vht mcs/nss in ieee80211_parse_tx_radiotap","id":"CVE-2021-47395"},"packages":[],"prev":{"headline":"hwmon: (mlxreg-fan) Return non-zero value when fan current state is enforced from sysfs","id":"CVE-2021-47393"},"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":"2026-08-05","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel netfilter subsystem allows local attackers to potentially execute code or escalate privileges via race conditions.","url":"https://insights.sbomify.com/CVE-2021-47394/"}