{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47299 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47299 is a medium-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-2021-47299 and fix it if it is affected.\n\nWhat it is: CVE-2021-47299 is a medium-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-2021-47299 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-2021-47299/ (Markdown: https://insights.sbomify.com/CVE-2021-47299/index.md)","id":"CVE-2021-47299","markdown":"https://insights.sbomify.com/CVE-2021-47299/index.md","name":"CVE-2021-47299","record":{"aliases":["DEBIAN-CVE-2021-47299","GHSA-8fm5-v3c4-vrmq","UBUNTU-CVE-2021-47299"],"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 vulnerability in the Linux kernel's XDP link release allows local attackers to potentially execute arbitrary code or escalate privileges.","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":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-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxdp, net: Fix use-after-free in bpf_xdp_link_release\n\nThe problem occurs between dev_get_by_index() and dev_xdp_attach_link().\nAt this point, dev_xdp_uninstall() is called. Then xdp link will not be\ndetached automatically when dev is released. But link-\u003edev already\npoints to dev, when xdp link is released, dev will still be accessed,\nbut dev has been released.\n\ndev_get_by_index()        |\nlink-\u003edev = dev           |\n                          |      rtnl_lock()\n                          |      unregister_netdevice_many()\n                          |          dev_xdp_uninstall()\n                          |      rtnl_unlock()\nrtnl_lock();              |\ndev_xdp_attach_link()     |\nrtnl_unlock();            |\n                          |      netdev_run_todo() // dev released\nbpf_xdp_link_release()    |\n    /* access dev.        |\n       use-after-free */  |\n\n[   45.966867] BUG: KASAN: use-after-free in bpf_xdp_link_release+0x3b8/0x3d0\n[   45.967619] Read of size 8 at addr ffff00000f9980c8 by task a.out/732\n[   45.968297]\n[   45.968502] CPU: 1 PID: 732 Comm: a.out Not tainted 5.13.0+ #22\n[   45.969222] Hardware name: linux,dummy-virt (DT)\n[   45.969795] Call trace:\n[   45.970106]  dump_backtrace+0x0/0x4c8\n[   45.970564]  show_stack+0x30/0x40\n[   45.970981]  dump_stack_lvl+0x120/0x18c\n[   45.971470]  print_address_description.constprop.0+0x74/0x30c\n[   45.972182]  kasan_report+0x1e8/0x200\n[   45.972659]  __asan_report_load8_noabort+0x2c/0x50\n[   45.973273]  bpf_xdp_link_release+0x3b8/0x3d0\n[   45.973834]  bpf_link_free+0xd0/0x188\n[   45.974315]  bpf_link_put+0x1d0/0x218\n[   45.974790]  bpf_link_release+0x3c/0x58\n[   45.975291]  __fput+0x20c/0x7e8\n[   45.975706]  ____fput+0x24/0x30\n[   45.976117]  task_work_run+0x104/0x258\n[   45.976609]  do_notify_resume+0x894/0xaf8\n[   45.977121]  work_pending+0xc/0x328\n[   45.977575]\n[   45.977775] The buggy address belongs to the page:\n[   45.978369] page:fffffc00003e6600 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f998\n[   45.979522] flags: 0x7fffe0000000000(node=0|zone=0|lastcpupid=0x3ffff)\n[   45.980349] raw: 07fffe0000000000 fffffc00003e6708 ffff0000dac3c010 0000000000000000\n[   45.981309] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000\n[   45.982259] page dumped because: kasan: bad access detected\n[   45.982948]\n[   45.983153] Memory state around the buggy address:\n[   45.983753]  ffff00000f997f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n[   45.984645]  ffff00000f998000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n[   45.985533] \u003effff00000f998080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n[   45.986419]                                               ^\n[   45.987112]  ffff00000f998100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n[   45.988006]  ffff00000f998180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n[   45.988895] ==================================================================\n[   45.989773] Disabling lock debugging due to kernel taint\n[   45.990552] Kernel panic - not syncing: panic_on_warn set ...\n[   45.991166] CPU: 1 PID: 732 Comm: a.out Tainted: G    B             5.13.0+ #22\n[   45.991929] Hardware name: linux,dummy-virt (DT)\n[   45.992448] Call trace:\n[   45.992753]  dump_backtrace+0x0/0x4c8\n[   45.993208]  show_stack+0x30/0x40\n[   45.993627]  dump_stack_lvl+0x120/0x18c\n[   45.994113]  dump_stack+0x1c/0x34\n[   45.994530]  panic+0x3a4/0x7d8\n[   45.994930]  end_report+0x194/0x198\n[   45.995380]  kasan_report+0x134/0x200\n[   45.995850]  __asan_report_load8_noabort+0x2c/0x50\n[   45.996453]  bpf_xdp_link_release+0x3b8/0x3d0\n[   45.997007]  bpf_link_free+0xd0/0x188\n[   45.997474]  bpf_link_put+0x1d0/0x218\n[   45.997942]  bpf_link_release+0x3c/0x58\n[   45.998429]  __fput+0x20c/0x7e8\n[   45.998833]  ____fput+0x24/0x30\n[   45.999247]  task_work_run+0x104/0x258\n[   45.999731]  do_notify_resume+0x894/0xaf8\n[   46.000236]  work_pending\n---truncated---","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":"xdp, net: Fix use-after-free in bpf_xdp_link_release","id":"CVE-2021-47299","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":3,"next":{"headline":"bpf: Fix tail_call_reachable rejection for interpreter when jit failed","id":"CVE-2021-47300"},"packages":[],"prev":{"headline":"bpf, sockmap: Fix potential memory leak on unlikely error case","id":"CVE-2021-47298"},"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 use-after-free vulnerability in the Linux kernel's XDP link release allows local attackers to potentially execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2021-47299/"}