CVE-2026-64124 (GCVE-0-2026-64124)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: devmem: reject dma-buf bind with non-page-aligned size or SG length net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be PAGE_SIZE multiples without checking: - tx_vec is sized dmabuf->size / PAGE_SIZE, and net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size before indexing tx_vec[virt_addr / PAGE_SIZE]. With size = N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base = N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past. - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner() covers the full byte len, so a non-page-multiple non-final sg desyncs num_niovs from the gen_pool region for every later sg, on both RX and TX. dma-buf does not require page-aligned sizes, so the bind path has to enforce what its own indexing assumes. Reject both with -EINVAL. The size check is TX-only (only tx_vec is sized off dmabuf->size); the SG-length check covers both directions.
References
Impacted products
Vendor Product Version
Linux Linux Version: bd61848900bff597764238f3a8ec67c815cd316e
Version: bd61848900bff597764238f3a8ec67c815cd316e
Version: bd61848900bff597764238f3a8ec67c815cd316e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/devmem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "134c517dfa63203287b2aad6558017f42435a02e",
              "status": "affected",
              "version": "bd61848900bff597764238f3a8ec67c815cd316e",
              "versionType": "git"
            },
            {
              "lessThan": "d5008e4e4ee6b739256b796702a7d1aae1b5c3b4",
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              "version": "bd61848900bff597764238f3a8ec67c815cd316e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "bd61848900bff597764238f3a8ec67c815cd316e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/devmem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.35",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: devmem: reject dma-buf bind with non-page-aligned size or SG length\n\nnet_devmem_bind_dmabuf() trusts dmabuf-\u003esize and sg_dma_len() to be\nPAGE_SIZE multiples without checking:\n\n  - tx_vec is sized dmabuf-\u003esize / PAGE_SIZE, and\n    net_devmem_get_niov_at() only bounds-checks virt_addr \u003c dmabuf-\u003esize\n    before indexing tx_vec[virt_addr / PAGE_SIZE]. With size =\n    N*PAGE_SIZE + r (1 \u003c= r \u003c PAGE_SIZE), sendmsg() at iov_base =\n    N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past.\n\n  - owner-\u003earea.num_niovs = len / PAGE_SIZE while gen_pool_add_owner()\n    covers the full byte len, so a non-page-multiple non-final sg\n    desyncs num_niovs from the gen_pool region for every later sg, on\n    both RX and TX.\n\ndma-buf does not require page-aligned sizes, so the bind path has to\nenforce what its own indexing assumes. Reject both with -EINVAL.\n\nThe size check is TX-only (only tx_vec is sized off dmabuf-\u003esize); the\nSG-length check covers both directions."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local syscalls\u2014NETLINK_GENERIC netdev bind operations and sendmsg/recvmsg on TCP sockets\u2014not remote packet delivery. Network traffic can trigger RX allocations only after a local bind with a malformed dmabuf.\nAC:L - The attacker fully controls dmabuf size/SG layout at bind time and the virtual offset passed via sendmsg iovec bases, allowing reliable out-of-bounds indexing without races or victim-dependent timing.\nPR:L - TX bind intentionally lacks admin-perm; RX bind requires CAP_NET_ADMIN, which is obtainable in user namespaces via unshare. No real-root privileges are needed, only a local authorized user on a devmem-capable system.\nUI:N - No victim interaction is required; the attacker triggers the bug through their own netlink bind and socket operations.\nS:C - Corrupted net_iov metadata can program incorrect DMA addresses for NIC DMA operations, potentially impacting device memory outside the kernel\u0027s security authority\u2014a DMA boundary crossing inherent to the devmem subsystem.\nC:H - Out-of-bounds read of tx_vec leaks adjacent kernel heap contents (kernel pointers), and heap corruption from misindexed niovs arrays can be leveraged for arbitrary memory disclosure.\nI:H - Out-of-bounds writes to the niovs array corrupt adjacent kernel heap objects, and use of attacker-influenced pointers in skb fragment setup enables memory corruption exploitable for control-flow hijacking.\nA:H - Dereferencing corrupted net_iov pointers or corrupting heap metadata via out-of-bounds access can cause kernel oops, panic, or hang during TX sendmsg or RX packet processing."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:30.822Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/134c517dfa63203287b2aad6558017f42435a02e"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5008e4e4ee6b739256b796702a7d1aae1b5c3b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/4eb82ba543421e9e38cc14e4e82058b78850df50"
        }
      ],
      "title": "net: devmem: reject dma-buf bind with non-page-aligned size or SG length",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64124",
    "datePublished": "2026-07-19T15:40:21.879Z",
    "dateReserved": "2026-07-19T07:54:57.036Z",
    "dateUpdated": "2026-08-05T12:39:30.822Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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