{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47418 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47418 is a medium-severity 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-2021-47418 and fix it if it is affected.\n\nWhat it is: CVE-2021-47418 is a medium-severity 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-2021-47418 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-2021-47418/ (Markdown: https://insights.sbomify.com/CVE-2021-47418/index.md)","id":"CVE-2021-47418","markdown":"https://insights.sbomify.com/CVE-2021-47418/index.md","name":"CVE-2021-47418","record":{"aliases":["DEBIAN-CVE-2021-47418","GHSA-8p4f-x4p9-vv9j","UBUNTU-CVE-2021-47418"],"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 local attacker can trigger a kernel crash via specific traffic control commands, causing a 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_sched: fix NULL deref in fifo_set_limit()\n\nsyzbot reported another NULL deref in fifo_set_limit() [1]\n\nI could repro the issue with :\n\nunshare -n\ntc qd add dev lo root handle 1:0 tbf limit 200000 burst 70000 rate 100Mbit\ntc qd replace dev lo parent 1:0 pfifo_fast\ntc qd change dev lo root handle 1:0 tbf limit 300000 burst 70000 rate 100Mbit\n\npfifo_fast does not have a change() operation.\nMake fifo_set_limit() more robust about this.\n\n[1]\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nPGD 1cf99067 P4D 1cf99067 PUD 7ca49067 PMD 0\nOops: 0010 [#1] PREEMPT SMP KASAN\nCPU: 1 PID: 14443 Comm: syz-executor959 Not tainted 5.15.0-rc3-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nRIP: 0010:0x0\nCode: Unable to access opcode bytes at RIP 0xffffffffffffffd6.\nRSP: 0018:ffffc9000e2f7310 EFLAGS: 00010246\nRAX: dffffc0000000000 RBX: ffffffff8d6ecc00 RCX: 0000000000000000\nRDX: 0000000000000000 RSI: ffff888024c27910 RDI: ffff888071e34000\nRBP: ffff888071e34000 R08: 0000000000000001 R09: ffffffff8fcfb947\nR10: 0000000000000001 R11: 0000000000000000 R12: ffff888024c27910\nR13: ffff888071e34018 R14: 0000000000000000 R15: ffff88801ef74800\nFS:  00007f321d897700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: ffffffffffffffd6 CR3: 00000000722c3000 CR4: 00000000003506e0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n fifo_set_limit net/sched/sch_fifo.c:242 [inline]\n fifo_set_limit+0x198/0x210 net/sched/sch_fifo.c:227\n tbf_change+0x6ec/0x16d0 net/sched/sch_tbf.c:418\n qdisc_change net/sched/sch_api.c:1332 [inline]\n tc_modify_qdisc+0xd9a/0x1a60 net/sched/sch_api.c:1634\n rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572\n netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504\n netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]\n netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340\n netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929\n sock_sendmsg_nosec net/socket.c:704 [inline]\n sock_sendmsg+0xcf/0x120 net/socket.c:724\n ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409\n ___sys_sendmsg+0xf3/0x170 net/socket.c:2463\n __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae","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_sched: fix NULL deref in fifo_set_limit()","id":"CVE-2021-47418","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":8,"next":{"headline":"net/sched: sch_taprio: properly cancel timer from taprio_destroy()","id":"CVE-2021-47419"},"packages":[],"prev":{"headline":"libbpf: Fix memory leak in strset","id":"CVE-2021-47417"},"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 local attacker can trigger a kernel crash via specific traffic control commands, causing a denial of service.","url":"https://insights.sbomify.com/CVE-2021-47418/"}