{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-54173","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-12-30T12:06:44.496Z","datePublished":"2025-12-30T12:08:46.842Z","dateUpdated":"2026-08-05T09:17:50.116Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T09:17:50.116Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Disable preemption in bpf_event_output\n\nWe received report [1] of kernel crash, which is caused by\nusing nesting protection without disabled preemption.\n\nThe bpf_event_output can be called by programs executed by\nbpf_prog_run_array_cg function that disabled migration but\nkeeps preemption enabled.\n\nThis can cause task to be preempted by another one inside the\nnesting protection and lead eventually to two tasks using same\nperf_sample_data buffer and cause crashes like:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000001\n  #PF: supervisor instruction fetch in kernel mode\n  #PF: error_code(0x0010) - not-present page\n  ...\n  ? perf_output_sample+0x12a/0x9a0\n  ? finish_task_switch.isra.0+0x81/0x280\n  ? perf_event_output+0x66/0xa0\n  ? bpf_event_output+0x13a/0x190\n  ? bpf_event_output_data+0x22/0x40\n  ? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb\n  ? xa_load+0x87/0xe0\n  ? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0\n  ? release_sock+0x3e/0x90\n  ? sk_setsockopt+0x1a1/0x12f0\n  ? udp_pre_connect+0x36/0x50\n  ? inet_dgram_connect+0x93/0xa0\n  ? __sys_connect+0xb4/0xe0\n  ? udp_setsockopt+0x27/0x40\n  ? __pfx_udp_push_pending_frames+0x10/0x10\n  ? __sys_setsockopt+0xdf/0x1a0\n  ? __x64_sys_connect+0xf/0x20\n  ? do_syscall_64+0x3a/0x90\n  ? entry_SYSCALL_64_after_hwframe+0x72/0xdc\n\nFixing this by disabling preemption in bpf_event_output.\n\n[1] https://github.com/cilium/cilium/issues/26756"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable window is entered from local syscalls (connect/sendmsg/setsockopt/close) that invoke cgroup BPF programs via bpf_prog_run_array_cg in preemptible process context. Remote packets only reach this code through softirq paths where preemption is already disabled, so exploitation requires local execution.\nAC:L - The attacker controls both sides of the race — multiple threads pinned to the same CPU repeatedly invoking the helper, plus self-generated scheduling pressure to force preemption inside the unprotected nest-level window. The required preemptible kernel (CONFIG_PREEMPT/PREEMPT_DYNAMIC/PREEMPT_RT) and a perf-emitting eBPF agent are the default in Android, container, and cloud deployments.\nPR:L - Any unprivileged local process — including code confined inside a container or pod — triggers the cgroup BPF program merely by calling connect(), sendmsg(), or setsockopt(); no capability, CAP_BPF, or namespace privilege is required on the triggering side.\nUI:N - No victim action is needed; the attacker's own syscalls drive both racing invocations, and the presence of an attached eBPF monitoring program is ambient system configuration rather than user interaction.\nS:U - The corruption and its consequences are confined to the kernel's own security authority with no crossing of a hypervisor, IOMMU, or sandbox boundary. This is standard in-kernel memory corruption / privilege escalation.\nC:H - A hijacked perf_sample_data leaves sd->raw pointing at a dead kernel stack frame, so __output_copy() streams frag->size bytes from an unvalidated frag->data pointer into the perf ring buffer that userspace mmaps — an arbitrary kernel memory read primitive into attacker-readable memory.\nI:H - perf_output_sample() performs an indirect call through frag->copy read from the stale stack frame (__output_custom), which the mainline reports observed as executing an NX-protected page and fetching instructions from address 0x1. Since the stale frame belongs to an attacker-controlled task, this is a groomable control-flow hijack primitive.\nA:H - The bug was reported from production as a hard kernel crash — NULL pointer dereference / supervisor instruction fetch oops in perf_output_sample — and can be triggered repeatedly by any local user, producing a reliable denial of service."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/bpf_trace.c"],"versions":[{"version":"2a916f2f546ca1c1e3323e2a4269307f6d9890eb","lessThan":"3048cb0dc0cc9dc74ed93690dffef00733bcad5b","status":"affected","versionType":"git"},{"version":"2a916f2f546ca1c1e3323e2a4269307f6d9890eb","lessThan":"c81bdf8f9f2b002d217c3d5357cdea9f2b82ff90","status":"affected","versionType":"git"},{"version":"2a916f2f546ca1c1e3323e2a4269307f6d9890eb","lessThan":"36dd8ca330b76585640ed32255a3c99f901e1502","status":"affected","versionType":"git"},{"version":"2a916f2f546ca1c1e3323e2a4269307f6d9890eb","lessThan":"063c9ce8e74e07bf94f99cd13146f42867875e8b","status":"affected","versionType":"git"},{"version":"2a916f2f546ca1c1e3323e2a4269307f6d9890eb","lessThan":"d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/bpf_trace.c"],"versions":[{"version":"5.7","status":"affected"},{"version":"0","lessThan":"5.7","status":"unaffected","versionType":"semver"},{"version":"5.10.190","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.126","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.45","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.4.10","lessThanOrEqual":"6.4.*","status":"unaffected","versionType":"semver"},{"version":"6.5","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.10.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.15.126"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.1.45"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.4.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.5"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/3048cb0dc0cc9dc74ed93690dffef00733bcad5b"},{"url":"https://git.kernel.org/stable/c/c81bdf8f9f2b002d217c3d5357cdea9f2b82ff90"},{"url":"https://git.kernel.org/stable/c/36dd8ca330b76585640ed32255a3c99f901e1502"},{"url":"https://git.kernel.org/stable/c/063c9ce8e74e07bf94f99cd13146f42867875e8b"},{"url":"https://git.kernel.org/stable/c/d62cc390c2e99ae267ffe4b8d7e2e08b6c758c32"}],"title":"bpf: Disable preemption in bpf_event_output","x_generator":{"engine":"bippy-1.2.0"}}}}