{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47222 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47222 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-2021-47222 and fix it if it is affected.\n\nWhat it is: CVE-2021-47222 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-2021-47222 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-2021-47222/ (Markdown: https://insights.sbomify.com/CVE-2021-47222/index.md)","id":"CVE-2021-47222","markdown":"https://insights.sbomify.com/CVE-2021-47222/index.md","name":"CVE-2021-47222","record":{"aliases":["DEBIAN-CVE-2021-47222","GHSA-h423-6g7m-qpqq","UBUNTU-CVE-2021-47222"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel bridge","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel bridge module allows attackers to cause a denial of service via crafted network traffic.","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\nnet: bridge: fix vlan tunnel dst refcnt when egressing\n\nThe egress tunnel code uses dst_clone() and directly sets the result\nwhich is wrong because the entry might have 0 refcnt or be already deleted,\ncausing number of problems. It also triggers the WARN_ON() in dst_hold()[1]\nwhen a refcnt couldn't be taken. Fix it by using dst_hold_safe() and\nchecking if a reference was actually taken before setting the dst.\n\n[1] dmesg WARN_ON log and following refcnt errors\n WARNING: CPU: 5 PID: 38 at include/net/dst.h:230 br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]\n Modules linked in: 8021q garp mrp bridge stp llc bonding ipv6 virtio_net\n CPU: 5 PID: 38 Comm: ksoftirqd/5 Kdump: loaded Tainted: G        W         5.13.0-rc3+ #360\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014\n RIP: 0010:br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]\n Code: e8 85 bc 01 e1 45 84 f6 74 90 45 31 f6 85 db 48 c7 c7 a0 02 19 a0 41 0f 94 c6 31 c9 31 d2 44 89 f6 e8 64 bc 01 e1 85 db 75 02 \u003c0f\u003e 0b 31 c9 31 d2 44 89 f6 48 c7 c7 70 02 19 a0 e8 4b bc 01 e1 49\n RSP: 0018:ffff8881003d39e8 EFLAGS: 00010246\n RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\n RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa01902a0\n RBP: ffff8881040c6700 R08: 0000000000000000 R09: 0000000000000001\n R10: 2ce93d0054fe0d00 R11: 54fe0d00000e0000 R12: ffff888109515000\n R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000401\n FS:  0000000000000000(0000) GS:ffff88822bf40000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f42ba70f030 CR3: 0000000109926000 CR4: 00000000000006e0\n Call Trace:\n  br_handle_vlan+0xbc/0xca [bridge]\n  __br_forward+0x23/0x164 [bridge]\n  deliver_clone+0x41/0x48 [bridge]\n  br_handle_frame_finish+0x36f/0x3aa [bridge]\n  ? skb_dst+0x2e/0x38 [bridge]\n  ? br_handle_ingress_vlan_tunnel+0x3e/0x1c8 [bridge]\n  ? br_handle_frame_finish+0x3aa/0x3aa [bridge]\n  br_handle_frame+0x2c3/0x377 [bridge]\n  ? __skb_pull+0x33/0x51\n  ? vlan_do_receive+0x4f/0x36a\n  ? br_handle_frame_finish+0x3aa/0x3aa [bridge]\n  __netif_receive_skb_core+0x539/0x7c6\n  ? __list_del_entry_valid+0x16e/0x1c2\n  __netif_receive_skb_list_core+0x6d/0xd6\n  netif_receive_skb_list_internal+0x1d9/0x1fa\n  gro_normal_list+0x22/0x3e\n  dev_gro_receive+0x55b/0x600\n  ? detach_buf_split+0x58/0x140\n  napi_gro_receive+0x94/0x12e\n  virtnet_poll+0x15d/0x315 [virtio_net]\n  __napi_poll+0x2c/0x1c9\n  net_rx_action+0xe6/0x1fb\n  __do_softirq+0x115/0x2d8\n  run_ksoftirqd+0x18/0x20\n  smpboot_thread_fn+0x183/0x19c\n  ? smpboot_unregister_percpu_thread+0x66/0x66\n  kthread+0x10a/0x10f\n  ? kthread_mod_delayed_work+0xb6/0xb6\n  ret_from_fork+0x22/0x30\n ---[ end trace 49f61b07f775fd2b ]---\n dst_release: dst:00000000c02d677a refcnt:-1\n dst_release underflow","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 refcnt when egressing","id":"CVE-2021-47222","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":6,"next":{"headline":"net: bridge: fix vlan tunnel dst null pointer dereference","id":"CVE-2021-47223"},"packages":[],"prev":{"headline":"mm/slub: actually fix freelist pointer vs redzoning","id":"CVE-2021-47221"},"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 vulnerability in the Linux kernel bridge module allows attackers to cause a denial of service via crafted network traffic.","url":"https://insights.sbomify.com/CVE-2021-47222/"}