{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47588 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47588 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jun 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-2021-47588 and fix it if it is affected.\n\nWhat it is: CVE-2021-47588 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jun 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-2021-47588 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-2021-47588/ (Markdown: https://insights.sbomify.com/CVE-2021-47588/index.md)","id":"CVE-2021-47588","markdown":"https://insights.sbomify.com/CVE-2021-47588/index.md","name":"CVE-2021-47588","record":{"aliases":["DEBIAN-CVE-2021-47588","GHSA-g3vj-5c3x-wjr4","UBUNTU-CVE-2021-47588"],"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 double-free vulnerability in the Linux kernel's SIT tunnel initialization allows local attackers to cause a system crash via namespace creation.","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":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsit: do not call ipip6_dev_free() from sit_init_net()\n\nipip6_dev_free is sit dev-\u003epriv_destructor, already called\nby register_netdevice() if something goes wrong.\n\nAlternative would be to make ipip6_dev_free() robust against\nmultiple invocations, but other drivers do not implement this\nstrategy.\n\nsyzbot reported:\n\ndst_release underflow\nWARNING: CPU: 0 PID: 5059 at net/core/dst.c:173 dst_release+0xd8/0xe0 net/core/dst.c:173\nModules linked in:\nCPU: 1 PID: 5059 Comm: syz-executor.4 Not tainted 5.16.0-rc5-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nRIP: 0010:dst_release+0xd8/0xe0 net/core/dst.c:173\nCode: 4c 89 f2 89 d9 31 c0 5b 41 5e 5d e9 da d5 44 f9 e8 1d 90 5f f9 c6 05 87 48 c6 05 01 48 c7 c7 80 44 99 8b 31 c0 e8 e8 67 29 f9 \u003c0f\u003e 0b eb 85 0f 1f 40 00 53 48 89 fb e8 f7 8f 5f f9 48 83 c3 a8 48\nRSP: 0018:ffffc9000aa5faa0 EFLAGS: 00010246\nRAX: d6894a925dd15a00 RBX: 00000000ffffffff RCX: 0000000000040000\nRDX: ffffc90005e19000 RSI: 000000000003ffff RDI: 0000000000040000\nRBP: 0000000000000000 R08: ffffffff816a1f42 R09: ffffed1017344f2c\nR10: ffffed1017344f2c R11: 0000000000000000 R12: 0000607f462b1358\nR13: 1ffffffff1bfd305 R14: ffffe8ffffcb1358 R15: dffffc0000000000\nFS:  00007f66c71a2700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f88aaed5058 CR3: 0000000023e0f000 CR4: 00000000003506f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n dst_cache_destroy+0x107/0x1e0 net/core/dst_cache.c:160\n ipip6_dev_free net/ipv6/sit.c:1414 [inline]\n sit_init_net+0x229/0x550 net/ipv6/sit.c:1936\n ops_init+0x313/0x430 net/core/net_namespace.c:140\n setup_net+0x35b/0x9d0 net/core/net_namespace.c:326\n copy_net_ns+0x359/0x5c0 net/core/net_namespace.c:470\n create_new_namespaces+0x4ce/0xa00 kernel/nsproxy.c:110\n unshare_nsproxy_namespaces+0x11e/0x180 kernel/nsproxy.c:226\n ksys_unshare+0x57d/0xb50 kernel/fork.c:3075\n __do_sys_unshare kernel/fork.c:3146 [inline]\n __se_sys_unshare kernel/fork.c:3144 [inline]\n __x64_sys_unshare+0x34/0x40 kernel/fork.c:3144\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7f66c882ce99\nCode: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007f66c71a2168 EFLAGS: 00000246 ORIG_RAX: 0000000000000110\nRAX: ffffffffffffffda RBX: 00007f66c893ff60 RCX: 00007f66c882ce99\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000048040200\nRBP: 00007f66c8886ff1 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007fff6634832f R14: 00007f66c71a2300 R15: 0000000000022000\n \u003c/TASK\u003e","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":"sit: do not call ipip6_dev_free() from sit_init_net()","id":"CVE-2021-47588","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":"igbvf: fix double free in `igbvf_probe`","id":"CVE-2021-47589"},"packages":[],"prev":{"headline":"net: systemport: Add global locking for descriptor lifecycle","id":"CVE-2021-47587"},"products":["Linux"],"published":"2024-06-19","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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A double-free vulnerability in the Linux kernel's SIT tunnel initialization allows local attackers to cause a system crash via namespace creation.","url":"https://insights.sbomify.com/CVE-2021-47588/"}