{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-90358",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-90358"
  ],
  "published": "2026-09-17T16:10:40Z",
  "summary": "bpf, x86: Fix trampoline stack size for 128-bit arguments",
  "details": "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.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": null,
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-90358"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4aed2346fa9b88d458eeb8c01123f3c07585a675"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/40f3bfbbb222b92278f3797614b70f68d46824ac"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a6d7d7a253c550e74b0651897fe313c2f9b2301f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/814cba835ef648e0c5eb79505c96c0493b29eea6"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-18T17:55:42Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "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."
    }
  }
}