{"id":"CVE-2026-90358","state":"PUBLISHED","title":"bpf, x86: Fix trampoline stack size for 128-bit arguments","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, x86: Fix trampoline stack size for 128-bit arguments\n\nbtf_distill_func_proto() accepts a function argument up to 16 bytes, so a\n128-bit scalar such as __int128 reaches the x86 trampoline with\narg_size == 16. But the current implementation assumes an __int128\nargument only needs one register, so the register save area is\nunder-allocated and save_args() overwrites adjacent stack slots.\n\nCompute the register count from arg_size for all arguments to fix it.","publishedAt":"2026-09-17T16:09:03.531Z","updatedAt":"2026-10-30T12:35:20.664Z","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":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"2189232984b45ac8281c80484ab9f67b380a2ca1","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"7f96bf0d24b2acc0732906b60a10f06783f2470d","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"4aed2346fa9b88d458eeb8c01123f3c07585a675","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"40f3bfbbb222b92278f3797614b70f68d46824ac","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"a6d7d7a253c550e74b0651897fe313c2f9b2301f","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"814cba835ef648e0c5eb79505c96c0493b29eea6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/net/bpf_jit_comp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","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":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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":["arch/x86/net/bpf_jit_comp.c"]}],"references":["https://git.kernel.org/stable/c/2189232984b45ac8281c80484ab9f67b380a2ca1","https://git.kernel.org/stable/c/7f96bf0d24b2acc0732906b60a10f06783f2470d","https://git.kernel.org/stable/c/4aed2346fa9b88d458eeb8c01123f3c07585a675","https://git.kernel.org/stable/c/40f3bfbbb222b92278f3797614b70f68d46824ac","https://git.kernel.org/stable/c/a6d7d7a253c550e74b0651897fe313c2f9b2301f","https://git.kernel.org/stable/c/814cba835ef648e0c5eb79505c96c0493b29eea6"],"weaknesses":[],"ingestedAt":"2026-10-30T12:54:04.478Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90358.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90358","state":"PUBLISHED","datePublished":"2026-09-17T16:09:03.531Z","dateUpdated":"2026-10-30T12:35:20.664Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.806Z"},"containers":{"cna":{"title":"bpf, x86: Fix trampoline stack size for 128-bit arguments","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, x86: Fix trampoline stack size for 128-bit arguments\n\nbtf_distill_func_proto() accepts a function argument up to 16 bytes, so a\n128-bit scalar such as __int128 reaches the x86 trampoline with\narg_size == 16. But the current implementation assumes an __int128\nargument only needs one register, so the register save area is\nunder-allocated and save_args() overwrites adjacent stack slots.\n\nCompute the register count from arg_size for all arguments to fix it."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"2189232984b45ac8281c80484ab9f67b380a2ca1","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"7f96bf0d24b2acc0732906b60a10f06783f2470d","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"4aed2346fa9b88d458eeb8c01123f3c07585a675","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"40f3bfbbb222b92278f3797614b70f68d46824ac","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"a6d7d7a253c550e74b0651897fe313c2f9b2301f","versionType":"git"},{"version":"a9c5ad31fbdc4dec6d266fe22e51de1ad6d1bcf2","status":"affected","lessThan":"814cba835ef648e0c5eb79505c96c0493b29eea6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/net/bpf_jit_comp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","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":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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":["arch/x86/net/bpf_jit_comp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2189232984b45ac8281c80484ab9f67b380a2ca1"},{"url":"https://git.kernel.org/stable/c/7f96bf0d24b2acc0732906b60a10f06783f2470d"},{"url":"https://git.kernel.org/stable/c/4aed2346fa9b88d458eeb8c01123f3c07585a675"},{"url":"https://git.kernel.org/stable/c/40f3bfbbb222b92278f3797614b70f68d46824ac"},{"url":"https://git.kernel.org/stable/c/a6d7d7a253c550e74b0651897fe313c2f9b2301f"},{"url":"https://git.kernel.org/stable/c/814cba835ef648e0c5eb79505c96c0493b29eea6"}],"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 under-allocation is in __arch_prepare_bpf_trampoline()/save_args() in arch/x86/net/bpf_jit_comp.c and is reached only when a local process issues bpf(BPF_PROG_LOAD) for BPF_PROG_TYPE_TRACING fentry/fexit and bpf(BPF_LINK_CREATE) against a BTF function with a 16-byte integer argument. BPF is a local syscall vector, not a network protocol parser.\nAC:L - The attacker selects an attach target whose BTF has arg_size==16 without BTF_FMODEL_STRUCT_ARG (e.g. bpf_testmod_test_int128_arg). __arch_prepare_bpf_trampoline() then under-counts nr_regs by one slot per such argument and save_args() deterministically overwrites the next stack slot; no race or uninfluenced layout is required.\nPR:L - bpf_prog_load() rejects BPF_PROG_TYPE_TRACING unless bpf_token_capable(CAP_BPF) and, via is_perfmon_prog_type(), bpf_token_capable(CAP_PERFMON). Those capabilities are delegable with BPF tokens and are scored Low, not init-namespace root, consistent with other BPF trampoline CVEs.\nUI:N - The attacker loads the fentry/fexit program, attaches it with BPF_LINK_CREATE, and invokes the target themselves (for bpf_testmod, a read of the module sysfs test file that calls bpf_testmod_test_int128_arg). No separate victim mount or click is required.\nS:U - save_args() overwrites the trampoline's own saved RBP and adjacent slots in the host kernel stack. That is in-kernel memory corruption on the same authority, not a KVM/Xen guest-to-host, IOMMU, or sandbox boundary crossing.\nC:H - The extra 8-byte store of the __int128's second register (RSI) lands in adjacent trampoline slots. On an fentry trampoline without a return-value slot that is saved RBP, so leave pivots RSP through argument contents and subsequent pops/unwinds can disclose kernel stack/memory.\nI:H - The same OOB store overwrites saved RBP (and with two 16-byte scalars, the return address at RBP+8). The trampoline epilogue then executes leave; ret on a corrupted frame, which is kernel stack memory corruption exploitable for a stack pivot and control-flow hijack.\nA:H - Overwriting saved RBP with the high half of a small __int128 (0 for bpf_testmod_test_int128_arg((__int128)1,...)) makes leave load a bogus frame pointer, so the following pop/ret oopses or panics the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:35:20.664Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}