{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-90143",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-90143"
  ],
  "published": "2026-09-17T16:10:40Z",
  "summary": "net: kcm: Hold RCU read lock while running BPF parser",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: kcm: Hold RCU read lock while running BPF parser\n\nkcm_parse_func_strparser() calls bpf_prog_run_pin_on_cpu() which\nprevents CPU migration, but does not establish an RCU read-side\ncritical section. Consequently, BPF map operations can trigger\nWARN_ON_ONCE(!bpf_rcu_lock_held()) when called from the KCM strparser\nprogram.\n\nHold the RCU read lock while running the program.",
  "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": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-90143"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/37108861cf7bd909d4a372069bcd61c8f489e232"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3c70d27e792a28bca650ddd8a9aa0fe3591ffec5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1d26a6e007d46babc7fa76e5a157dccf86cd55c0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b0e94ea63dbdcbfec9beb819cd5f8fa584809ef2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/21526f8a191a3c50622b8c10bd927870d780eae4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/292846223eaddba890e40699d2ab82ee5671798c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f392affef3c9ce64dfdde794df0579e0a7793440"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b0346dd64e4905291cc9c479f2e6cf1884ced4e6"
    }
  ],
  "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 missing rcu_read_lock is in kcm_parse_func_strparser(), reached after local socket(AF_KCM) and ioctl(SIOCKCMATTACH) installing the caller's BPF_PROG_TYPE_SOCKET_FILTER via bpf_prog_get_type(). A remote TCP peer can only feed an skb into strp_recv(); map helpers fire regardless of payload, and the BPF program is locally supplied.\nAC:L - kcm_attach() always calls strp_check_rcv(), which queues do_strp_work so parse_msg runs in process context under lock_sock() with BH enabled, so bpf_rcu_lock_held() is false. The attacker loads a SOCKET_FILTER that calls bpf_map_lookup_elem and can delete the same HASH key from their own map fd on another thread.\nPR:L - kcm_create() and kcm_ioctl(SIOCKCMATTACH) have no capable() check, and PF_KCM autoloads via MODULE_ALIAS_NETPROTO. bpf_prog_get_type(..., BPF_PROG_TYPE_SOCKET_FILTER) and HASH/ARRAY maps are the unprivileged types in bpf_prog_load()/map_create(); CAP_BPF in the init namespace is not required when unprivileged BPF is enabled.\nUI:N - The attacker opens their own AF_KCM and TCP sockets, loads their own SOCKET_FILTER, issues SIOCKCMATTACH, and either pre-queues TCP data so strp_check_rcv() runs the parser or writes the TCP peer themselves. No other user must mount a filesystem, open a device, or attach a program.\nS:U - A dangling htab_elem used by kcm_parse_func_strparser() is a host-kernel use-after-free that can escalate privileges inside the same kernel. It does not cross a KVM/Xen guest-host boundary or an IOMMU/DMA domain.\nC:H - bpf_map_lookup_elem() proceeds after WARN_ON_ONCE(!bpf_rcu_lock_held()) and __htab_map_lookup_elem() still returns a pointer. Concurrent htab delete via the attacker's map fd frees or freelist-reuses that htab_elem (bpf_mem_cache_free/pcpu_freelist_push) while the SOCKET_FILTER still reads the map value, disclosing kernel heap.\nI:H - The verifier treats the map-value pointer as writable, so the SOCKET_FILTER can store through the dangling htab_elem after free_htab_elem() reuses it, and bpf_map_update_elem() also runs without RCU from kcm_parse_func_strparser(). That is an arbitrary kernel write via heap reuse, not a bounded overwrite.\nA:H - Use of the dangling htab_elem in do_strp_work oopses or panics the kernel. Independently, bpf_map_lookup_elem()/__htab_map_lookup_elem() hit WARN_ON_ONCE(!bpf_rcu_lock_held()) on the first map helper from kcm_parse_func_strparser(), which is fatal on kernels booted with panic_on_warn."
    }
  }
}