bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check

{
  "id": "22bca0f6db16d8cd060ab3175ec43ca131152a4dae3dc625f40b2984b785c802",
  "url": "https://osv.dev/vulnerability/CVE-2026-74256",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check start and len are u32, so u64 last = start + len; evaluates start + len in 32-bit and wraps before storing it in last. The bounds check if (start >= offset + l || last > msg->sg.size) return -EINVAL; can then be passed with an out-of-range start/len, after which the pop loop runs off the end of the scatterlist and sk_msg_shift_left() calls put_page() on the empty msg->sg.end slot: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline] RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline] RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984 Call Trace: bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8 bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746 sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934 tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline] tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583 __sock_sendmsg+0x153/0x1c0 net/socket.c:802 __sys_sendto+0x326/0x430 net/socket.c:2265 __x64_sys_sendto+0xe3/0x100 net/socket.c:2268 do_syscall_64+0x14c/0x480 entry_SYSCALL_64_after_hwframe+0x77/0x7f Widen the addition with a (u64) cast so the bound is evaluated in 64-bit and a len near U32_MAX no longer wraps below msg->sg.size. While ",
    "evidence": "osv:CVE-2026-74256",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.261",
            "evidence": "/affected/1/ranges"
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            "evidence": "/affected/1/ranges"
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          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
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        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-74256",
      "aliases": [
        "CVE-2026-74256"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
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      "affected": [
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      "modified": "2026-10-28T02:30:42.102921742Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/17eb9832a10db2f7a80cb429ca2bc5038445a943",
        "https://git.kernel.org/stable/c/9ef44ed6fb0c1db01cfcc3de432a33e719713eb5",
        "https://git.kernel.org/stable/c/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54",
        "https://git.kernel.org/stable/c/ba5cc05dae8fce237d191c7ea96b1107a791e548",
        "https://git.kernel.org/stable/c/c05a0ec1cdced622a1a0c7d85679fe02f31033ec",
        "https://git.kernel.org/stable/c/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0",
        "https://git.kernel.org/stable/c/e09f7bd7273928b4089e6b71f8e992f2b356ca1b",
        "https://git.kernel.org/stable/c/fe09dd288722f1c749b7506c0b3e7841a7d85027",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74256.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74256",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74256.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74256",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510066,
  "published_at": "2026-08-15T05:57:34.956+00:00"
}