{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-98220 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-98220 is a vulnerability in Linux, published on 6 Oct 2026. 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-2026-98220 and fix it if it is affected.\n\nWhat it is: CVE-2026-98220 is a vulnerability in Linux, published on 6 Oct 2026. 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-2026-98220 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-98220/ (Markdown: https://insights.sbomify.com/CVE-2026-98220/index.md)","id":"CVE-2026-98220","markdown":"https://insights.sbomify.com/CVE-2026-98220/index.md","name":"CVE-2026-98220","record":{"aliases":["DEBIAN-CVE-2026-98220","GHSA-h6hx-xpp5-6vc3","UBUNTU-CVE-2026-98220"],"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 with BPF privileges can trigger a kernel NULL pointer dereference in sched_ext, causing a system crash.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix NULL sched deref in kfunc sub-sched error paths\n\nWhen the root scheduler has sub-scheds attached, the COMPAT kfunc\nwrappers scx_bpf_select_cpu_and() and scx_bpf_dsq_insert_vtime() refuse\nthe call and report to @p's scheduler:\n\n\tscx_error(scx_task_sched(p), \"... must be used\");\n\nThe wrappers are reachable with tasks that have no scheduler.\nscx_bpf_select_cpu_and() is in the select_cpu kfunc group, which\nscx_kfunc_context_filter() opens to BPF_PROG_TYPE_SYSCALL programs;\nscx_bpf_dsq_insert_vtime() is in the enqueue_dispatch group, which\nops.enqueue() and ops.dispatch() may call with any KF_RCU task -- the\ngroup has no kf_tasks validation, and scx_dsq_insert_preamble() checks\ntask ownership with scx_task_on_sched() precisely because @p may be an\narbitrary task.\n\nscx_task_sched(p) is p-\u003escx.sched, which is NULL for tasks past\nsched_ext_dead() -- which clears it via scx_disable_and_exit_task() on\nexit -- and for idle tasks, which the enable paths skip as they are\nnever scheduled through SCX. It is also an rcu_dereference_protected()\nthat expects @p's pi_lock or rq lock, which neither wrapper holds.\nPassing NULL to scx_error() reaches scx_vexit(), which dereferences\nsch-\u003eexit_info, oopsing the kernel.\n\nOne concrete trigger exercised while developing the fix: a\nBPF_PROG_TYPE_SYSCALL program calling the select_cpu_and wrapper on an\nexited-but-not-reaped task while a sub-scheduler was attached (its pid\nstays findable while the zombie is unreaped; faulting instruction is\nthe scx_vexit() prologue \"mov r15,[rdi+0x398]\" with RDI=NULL and 0x398\nthe offset of sch-\u003eexit_info):\n\n  sched_ext: BPF scheduler \"kfunc_subsched_null\" enabled\n  sched_ext: BPF sub-scheduler \"kfunc_subsched_null\" enabled\n  sched_ext: Unassociated program run_select_cpu_ (id 76)\n  BUG: kernel NULL pointer dereference, address: 0000000000000398\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  Oops: Oops: 0000 [#1] SMP NOPTI\n  CPU: 7 UID: 0 PID: 8201 Comm: kfunc_test_runn Tainted: G W\n  RIP: 0010:scx_vexit+0x25/0xa0\n  Code: ... \u003c4c\u003e 8b bf 98 03 00 00 ...\n  CR2: 0000000000000398\n  Call Trace:\n   \u003cTASK\u003e\n   __scx_exit+0x4f/0x70\n   scx_bpf_select_cpu_and+0xab/0xb0\n   bpf_prog_430ed61a7b66e03a_run_select_cpu_and+0x9c/0xe7\n   ? __x64_sys_bpf+0x2c/0x40\n   bpf_prog_test_run_syscall+0x130/0x2f0\n   __sys_bpf+0x930/0x10d0\n   ? __x64_sys_bpf+0x2c/0x40\n   __x64_sys_bpf+0x2c/0x40\n   do_syscall_64+0xbc/0x460\n   entry_SYSCALL_64_after_hwframe+0x76/0x7e\n   \u003c/TASK\u003e\n\nRead @p's scheduler under RCU instead, which the wrappers can do from\ntheir guard(rcu)(): fault it when it can be determined, and when it\ncan't be determined -- @p is a task past sched_ext_dead() or an idle\ntask -- there is nothing obviously wrong to report, so just refuse the\ncall as before without faulting any scheduler.\n\nThese COMPAT wrappers are scheduled for eventual removal once the\ndeprecation grace period elapses, but until then -- and regardless of\ntheir removal timeline -- they must not oops the kernel on a task they\nare handed.","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":"sched_ext: Fix NULL sched deref in kfunc sub-sched error paths","id":"CVE-2026-98220","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"KEYS: trusted: Fix tpm2_load_cmd() boundary check","id":"CVE-2026-98221"},"packages":[],"prev":{"headline":"sched_ext: Close the pre-enable ops error claim window","id":"CVE-2026-98219"},"products":["Linux"],"published":"2026-10-06","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A local attacker with BPF privileges can trigger a kernel NULL pointer dereference in sched_ext, causing a system crash.","url":"https://insights.sbomify.com/CVE-2026-98220/"}