{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47572 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47572 is a medium-severity vulnerability in Linux kernel, published on 24 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-2021-47572 and fix it if it is affected.\n\nWhat it is: CVE-2021-47572 is a medium-severity vulnerability in Linux kernel, published on 24 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-2021-47572 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-2021-47572/ (Markdown: https://insights.sbomify.com/CVE-2021-47572/index.md)","id":"CVE-2021-47572","markdown":"https://insights.sbomify.com/CVE-2021-47572/index.md","name":"CVE-2021-47572","record":{"aliases":["DEBIAN-CVE-2021-47572","UBUNTU-CVE-2021-47572"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A local attacker can cause a kernel crash by adding an IPv6 nexthop when IPv6 is disabled, leading to 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: nexthop: fix null pointer dereference when IPv6 is not enabled\n\nWhen we try to add an IPv6 nexthop and IPv6 is not enabled\n(!CONFIG_IPV6) we'll hit a NULL pointer dereference[1] in the error path\nof nh_create_ipv6() due to calling ipv6_stub-\u003efib6_nh_release. The bug\nhas been present since the beginning of IPv6 nexthop gateway support.\nCommit 1aefd3de7bc6 (\"ipv6: Add fib6_nh_init and release to stubs\") tells\nus that only fib6_nh_init has a dummy stub because fib6_nh_release should\nnot be called if fib6_nh_init returns an error, but the commit below added\na call to ipv6_stub-\u003efib6_nh_release in its error path. To fix it return\nthe dummy stub's -EAFNOSUPPORT error directly without calling\nipv6_stub-\u003efib6_nh_release in nh_create_ipv6()'s error path.\n\n[1]\n Output is a bit truncated, but it clearly shows the error.\n BUG: kernel NULL pointer dereference, address: 000000000000000000\n #PF: supervisor instruction fetch in kernel modede\n #PF: error_code(0x0010) - not-present pagege\n PGD 0 P4D 0\n Oops: 0010 [#1] PREEMPT SMP NOPTI\n CPU: 4 PID: 638 Comm: ip Kdump: loaded Not tainted 5.16.0-rc1+ #446\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014\n RIP: 0010:0x0\n Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.\n RSP: 0018:ffff888109f5b8f0 EFLAGS: 00010286^Ac\n RAX: 0000000000000000 RBX: ffff888109f5ba28 RCX: 0000000000000000\n RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881008a2860\n RBP: ffff888109f5b9d8 R08: 0000000000000000 R09: 0000000000000000\n R10: ffff888109f5b978 R11: ffff888109f5b948 R12: 00000000ffffff9f\n R13: ffff8881008a2a80 R14: ffff8881008a2860 R15: ffff8881008a2840\n FS:  00007f98de70f100(0000) GS:ffff88822bf00000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: ffffffffffffffd6 CR3: 0000000100efc000 CR4: 00000000000006e0\n Call Trace:\n  \u003cTASK\u003e\n  nh_create_ipv6+0xed/0x10c\n  rtm_new_nexthop+0x6d7/0x13f3\n  ? check_preemption_disabled+0x3d/0xf2\n  ? lock_is_held_type+0xbe/0xfd\n  rtnetlink_rcv_msg+0x23f/0x26a\n  ? check_preemption_disabled+0x3d/0xf2\n  ? rtnl_calcit.isra.0+0x147/0x147\n  netlink_rcv_skb+0x61/0xb2\n  netlink_unicast+0x100/0x187\n  netlink_sendmsg+0x37f/0x3a0\n  ? netlink_unicast+0x187/0x187\n  sock_sendmsg_nosec+0x67/0x9b\n  ____sys_sendmsg+0x19d/0x1f9\n  ? copy_msghdr_from_user+0x4c/0x5e\n  ? rcu_read_lock_any_held+0x2a/0x78\n  ___sys_sendmsg+0x6c/0x8c\n  ? asm_sysvec_apic_timer_interrupt+0x12/0x20\n  ? lockdep_hardirqs_on+0xd9/0x102\n  ? sockfd_lookup_light+0x69/0x99\n  __sys_sendmsg+0x50/0x6e\n  do_syscall_64+0xcb/0xf2\n  entry_SYSCALL_64_after_hwframe+0x44/0xae\n RIP: 0033:0x7f98dea28914\n Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 48 8d 05 e9 5d 0c 00 8b 00 85 c0 75 13 b8 2e 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 41 89 d4 55 48 89 f5 53\n RSP: 002b:00007fff859f5e68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e2e\n RAX: ffffffffffffffda RBX: 00000000619cb810 RCX: 00007f98dea28914\n RDX: 0000000000000000 RSI: 00007fff859f5ed0 RDI: 0000000000000003\n RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000008\n R10: fffffffffffffce6 R11: 0000000000000246 R12: 0000000000000001\n R13: 000055c0097ae520 R14: 000055c0097957fd R15: 00007fff859f63a0\n \u003c/TASK\u003e\n Modules linked in: bridge stp llc bonding virtio_net","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: nexthop: fix null pointer dereference when IPv6 is not enabled","id":"CVE-2021-47572","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":4,"next":{"headline":"This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.","id":"CVE-2021-47573"},"packages":[],"prev":{"headline":"staging: rtl8192e: Fix use after free in _rtl92e_pci_disconnect()","id":"CVE-2021-47571"},"products":["Linux"],"published":"2024-05-24","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 local attacker can cause a kernel crash by adding an IPv6 nexthop when IPv6 is disabled, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2021-47572/"}