{"id":"CVE-2026-89799","state":"PUBLISHED","title":"bpf: Disable preemption in bpf_get_stackid","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Disable preemption in bpf_get_stackid\n\nThe get_perf_callchain call needs disabled preemption plus we need\nit disabled as long as we access its returned trace entries buffer.\n\nNote the bpf_get_stackid_pe function is executed already with\npreemption disabled.","publishedAt":"2026-09-16T10:30:31.487Z","updatedAt":"2026-10-30T12:33:04.585Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"01fc93f670b3e759413a4d574c18ccfc636d2728","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"e79a70c2e97ae36bbdd371f0ce88a525f7b49f01","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"18c71e4b65ee60b8611fc071bdd7159f10185117","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"ccf481d73bce6e851cec364fe831c86fe66877cf","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"c4efdc1d4cb3e9183e41a1b2a5e0901dbbb31cdf","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"15f1bd8574662f1b7b26aaa2e23ebf4066f0117d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/stackmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/stackmap.c"]}],"references":["https://git.kernel.org/stable/c/01fc93f670b3e759413a4d574c18ccfc636d2728","https://git.kernel.org/stable/c/e79a70c2e97ae36bbdd371f0ce88a525f7b49f01","https://git.kernel.org/stable/c/18c71e4b65ee60b8611fc071bdd7159f10185117","https://git.kernel.org/stable/c/ccf481d73bce6e851cec364fe831c86fe66877cf","https://git.kernel.org/stable/c/c4efdc1d4cb3e9183e41a1b2a5e0901dbbb31cdf","https://git.kernel.org/stable/c/15f1bd8574662f1b7b26aaa2e23ebf4066f0117d"],"weaknesses":[],"ingestedAt":"2026-10-30T12:52:04.348Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89799.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89799","state":"PUBLISHED","datePublished":"2026-09-16T10:30:31.487Z","dateUpdated":"2026-10-30T12:33:04.585Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.767Z"},"containers":{"cna":{"title":"bpf: Disable preemption in bpf_get_stackid","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Disable preemption in bpf_get_stackid\n\nThe get_perf_callchain call needs disabled preemption plus we need\nit disabled as long as we access its returned trace entries buffer.\n\nNote the bpf_get_stackid_pe function is executed already with\npreemption disabled."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"01fc93f670b3e759413a4d574c18ccfc636d2728","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"e79a70c2e97ae36bbdd371f0ce88a525f7b49f01","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"18c71e4b65ee60b8611fc071bdd7159f10185117","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"ccf481d73bce6e851cec364fe831c86fe66877cf","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"c4efdc1d4cb3e9183e41a1b2a5e0901dbbb31cdf","versionType":"git"},{"version":"d5a3b1f691865be576c2bffa708549b8cdccda19","status":"affected","lessThan":"15f1bd8574662f1b7b26aaa2e23ebf4066f0117d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/stackmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.6","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/stackmap.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/01fc93f670b3e759413a4d574c18ccfc636d2728"},{"url":"https://git.kernel.org/stable/c/e79a70c2e97ae36bbdd371f0ce88a525f7b49f01"},{"url":"https://git.kernel.org/stable/c/18c71e4b65ee60b8611fc071bdd7159f10185117"},{"url":"https://git.kernel.org/stable/c/ccf481d73bce6e851cec364fe831c86fe66877cf"},{"url":"https://git.kernel.org/stable/c/c4efdc1d4cb3e9183e41a1b2a5e0901dbbb31cdf"},{"url":"https://git.kernel.org/stable/c/15f1bd8574662f1b7b26aaa2e23ebf4066f0117d"}],"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 - bpf_get_stackid is a tracing BPF helper (kprobe, tracepoint, raw_tp, perf_event, tracing/fentry) reached only after a local bpf(2) PROG_LOAD and attach; kernel CNA guidance classifies BPF as Local, with no network or USB path into this helper.\nAC:L - The attacker controls both sides of the race: a preemptible raw_tp/tracing program with a small STACK_TRACE map, and a same-CPU get_perf_callchain with larger max_depth that reuses the per-CPU entry after put_callchain_entry(). On PREEMPT kernels (e.g. Android) raw_tp uses migrate_disable only, so pinning and retries make the window reliably hittable.\nPR:L - Loading the required tracing programs needs CAP_BPF and CAP_PERFMON at bpf_prog_load(), and STACK_TRACE maps need CAP_BPF. Per kernel CNA guidance these are Low because BPF tokens and user namespaces can delegate them to non-init-namespace users, not only real root.\nUI:N - The attacker loads their own BPF program, attaches it to a tracepoint they can fire, and invokes bpf_get_stackid through their own syscalls or pinned threads; no victim mount, file open, or other user action is required.\nS:U - The out-of-bounds write corrupts the stack-map bucket slab inside the same host kernel security authority, enabling local privilege escalation; it does not cross a VM, IOMMU, or other distinct trust boundary.\nC:H - After put_callchain_entry(), a reused per-CPU entry can inflate trace->nr so memcpy/jhash2 and the build-id loop copy kernel instruction pointers past the attacker-sized stack_map_bucket, which is kernel memory corruption that can be turned into an arbitrary read primitive.\nI:H - Without a remaining size cap on the reused trace->nr, memcpy into the preallocated stack_map_bucket (sized to a small map value_size) or the bpf_stack_build_id store loop is an attacker-sized kernel heap OOB write, up to PERF_MAX_STACK_DEPTH frames, that can smash adjacent slab and hijack control flow.\nA:H - The same unbounded heap write past a small stack-map bucket causes a kernel oops or panic even when not fully weaponized, matching CNA guidance that any kernel crash or memory-corrupting OOB write is Availability High."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:33:04.585Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.18.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}