FKIE_CVE-2026-68386

Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-19 17:20
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Reject unhashed UDP sockets on sockmap update UDP sockets get SOCK_RCU_FREE set when (auto-)bound. This means sk_is_refcounted(unbound) = true, while sk_is_refcounted(bound) = false. Because sockmap accepts unbound UDP sockets, a BPF program can increment a socket's refcount via lookup. If the socket is subsequently bound, the transition from unbound to bound causes bpf_sk_release() to skip the decrement of the refcount, causing a memory leak. unreferenced object 0xffff88810bc2eb40 (size 1984): comm "test_progs", pid 2451, jiffies 4295320596 hex dump (first 32 bytes): 7f 00 00 01 7f 00 00 01 d2 04 1b b7 04 d2 00 00 ................ 02 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace (crc bdee079d): kmem_cache_alloc_noprof+0x557/0x660 sk_prot_alloc+0x69/0x240 sk_alloc+0x30/0x460 inet_create+0x2ce/0xf80 __sock_create+0x25b/0x5c0 __sys_socket+0x119/0x1d0 __x64_sys_socket+0x72/0xd0 do_syscall_64+0xa1/0x5f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Instead of special-casing for refcounted sockets, reject unhashed UDP sockets during sockmap updates, as there is no benefit to supporting those. This effectively reverts the commit under Fixes, with two exceptions: 1. sock_map_sk_state_allowed() maintains a fall-through `return true`. 2. In the spirit of commit b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage"), the proto::unhash BPF handler is not reintroduced. Historical note: this issue is related to commit 67312adc96b5 ("bpf: reject unhashed sockets in bpf_sk_assign").
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/17b7ef6b86112a4e61cee1e9009a4b318e3225c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2271276ac5279d2d204be7739a1a28d4ef6cf608
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/250474c69bc3fc48a5fc21d7c349f279caad947a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/66efd3368ae10d05e08fbe6425b50fdec7186ac7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ffe529e7127411806c8692fb1490f552c629dc2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8692655da369961128658cf8539334b6a960ecb0
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/sock_map.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2271276ac5279d2d204be7739a1a28d4ef6cf608",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            },
            {
              "lessThan": "7ffe529e7127411806c8692fb1490f552c629dc2",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            },
            {
              "lessThan": "17b7ef6b86112a4e61cee1e9009a4b318e3225c5",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            },
            {
              "lessThan": "250474c69bc3fc48a5fc21d7c349f279caad947a",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            },
            {
              "lessThan": "8692655da369961128658cf8539334b6a960ecb0",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            },
            {
              "lessThan": "66efd3368ae10d05e08fbe6425b50fdec7186ac7",
              "status": "affected",
              "version": "0c48eefae712c2fd91480346a07a1a9cd0f9470b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/sock_map.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Reject unhashed UDP sockets on sockmap update\n\nUDP sockets get SOCK_RCU_FREE set when (auto-)bound. This means\nsk_is_refcounted(unbound) = true, while sk_is_refcounted(bound) = false.\n\nBecause sockmap accepts unbound UDP sockets, a BPF program can increment a\nsocket\u0027s refcount via lookup. If the socket is subsequently bound, the\ntransition from unbound to bound causes bpf_sk_release() to skip the\ndecrement of the refcount, causing a memory leak.\n\nunreferenced object 0xffff88810bc2eb40 (size 1984):\n  comm \"test_progs\", pid 2451, jiffies 4295320596\n  hex dump (first 32 bytes):\n    7f 00 00 01 7f 00 00 01 d2 04 1b b7 04 d2 00 00  ................\n    02 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............\n  backtrace (crc bdee079d):\n    kmem_cache_alloc_noprof+0x557/0x660\n    sk_prot_alloc+0x69/0x240\n    sk_alloc+0x30/0x460\n    inet_create+0x2ce/0xf80\n    __sock_create+0x25b/0x5c0\n    __sys_socket+0x119/0x1d0\n    __x64_sys_socket+0x72/0xd0\n    do_syscall_64+0xa1/0x5f0\n    entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nInstead of special-casing for refcounted sockets, reject unhashed UDP\nsockets during sockmap updates, as there is no benefit to supporting those.\nThis effectively reverts the commit under Fixes, with two exceptions:\n\n1. sock_map_sk_state_allowed() maintains a fall-through `return true`.\n2. In the spirit of commit b8b8315e39ff (\"bpf, sockmap: Remove unhash\n   handler for BPF sockmap usage\"), the proto::unhash BPF handler is not\n   reintroduced.\n\nHistorical note: this issue is related to commit 67312adc96b5 (\"bpf: reject\nunhashed sockets in bpf_sk_assign\")."
    }
  ],
  "id": "CVE-2026-68386",
  "lastModified": "2026-08-19T17:20:47.260",
  "metrics": {},
  "published": "2026-08-10T13:20:31.823",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/17b7ef6b86112a4e61cee1e9009a4b318e3225c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2271276ac5279d2d204be7739a1a28d4ef6cf608"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/250474c69bc3fc48a5fc21d7c349f279caad947a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/66efd3368ae10d05e08fbe6425b50fdec7186ac7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7ffe529e7127411806c8692fb1490f552c629dc2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8692655da369961128658cf8539334b6a960ecb0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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