CVE-2026-46132 (GCVE-0-2026-46132)
Vulnerability from cvelistv5
Published
2026-05-28 09:35
Modified
2026-06-14 17:56
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack without initialisation: struct ifla_vf_broadcast vf_broadcast; The struct contains a single fixed 32-byte field: /* include/uapi/linux/if_link.h */ struct ifla_vf_broadcast { __u8 broadcast[32]; }; The function then copies dev->broadcast into it using dev->addr_len as the length: memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len); On Ethernet devices (the overwhelming majority of SR-IOV NICs) dev->addr_len is 6, so only the first 6 bytes of broadcast[] are written. The remaining 26 bytes retain whatever was previously on the kernel stack. The full struct is then handed to userspace via: nla_put(skb, IFLA_VF_BROADCAST, sizeof(vf_broadcast), &vf_broadcast) leaking up to 26 bytes of uninitialised kernel stack per VF per RTM_GETLINK request, repeatable. The other vf_* structs in the same function are explicitly zeroed for exactly this reason - see the memset() calls for ivi, vf_vlan_info, node_guid and port_guid a few lines above. vf_broadcast was simply missed when it was added. Reachability: any unprivileged local process can open AF_NETLINK / NETLINK_ROUTE without capabilities and send RTM_GETLINK with an IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per VF per request. Stack residue at this call site can include return addresses and transient sensitive data; KASAN with stack instrumentation, or KMSAN, will flag the nla_put() when reproduced. Zero the on-stack struct before the partial memcpy, matching the existing pattern used for the other vf_* structs in the same function.
Impacted products
Vendor Product Version
Linux Linux Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
Version: 75345f888f700c4ab2448287e35d48c760b202e6
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/rtnetlink.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "5.3"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.140",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.88",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "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": "5.10.258",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
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                  "vulnerable": true
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                  "vulnerable": true
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                  "versionStartIncluding": "5.3",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo\n\nrtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack\nwithout initialisation:\n\n\tstruct ifla_vf_broadcast vf_broadcast;\n\nThe struct contains a single fixed 32-byte field:\n\n\t/* include/uapi/linux/if_link.h */\n\tstruct ifla_vf_broadcast {\n\t\t__u8 broadcast[32];\n\t};\n\nThe function then copies dev-\u003ebroadcast into it using dev-\u003eaddr_len\nas the length:\n\n\tmemcpy(vf_broadcast.broadcast, dev-\u003ebroadcast, dev-\u003eaddr_len);\n\nOn Ethernet devices (the overwhelming majority of SR-IOV NICs)\ndev-\u003eaddr_len is 6, so only the first 6 bytes of broadcast[] are\nwritten. The remaining 26 bytes retain whatever was previously on\nthe kernel stack. The full struct is then handed to userspace via:\n\n\tnla_put(skb, IFLA_VF_BROADCAST,\n\t\tsizeof(vf_broadcast), \u0026vf_broadcast)\n\nleaking up to 26 bytes of uninitialised kernel stack per VF per\nRTM_GETLINK request, repeatable.\n\nThe other vf_* structs in the same function are explicitly zeroed\nfor exactly this reason - see the memset() calls for ivi,\nvf_vlan_info, node_guid and port_guid a few lines above.\nvf_broadcast was simply missed when it was added.\n\nReachability: any unprivileged local process can open AF_NETLINK /\nNETLINK_ROUTE without capabilities and send RTM_GETLINK with an\nIFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks\neach VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per\nVF per request. Stack residue at this call site can include return\naddresses and transient sensitive data; KASAN with stack\ninstrumentation, or KMSAN, will flag the nla_put() when reproduced.\n\nZero the on-stack struct before the partial memcpy, matching the\nexisting pattern used for the other vf_* structs in the same\nfunction."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:56:50.522Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/14271b401ec6a4bf0d88054106fc2956084717e1"
        },
        {
          "url": "https://git.kernel.org/stable/c/cccce3190ba4356432b9f22369b56123d3d89f0d"
        },
        {
          "url": "https://git.kernel.org/stable/c/a44fbb631cba646532f3948636626f81717365a7"
        },
        {
          "url": "https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00"
        },
        {
          "url": "https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8"
        },
        {
          "url": "https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5"
        },
        {
          "url": "https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011"
        },
        {
          "url": "https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0"
        }
      ],
      "title": "net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46132",
    "datePublished": "2026-05-28T09:35:47.047Z",
    "dateReserved": "2026-05-13T15:03:33.099Z",
    "dateUpdated": "2026-06-14T17:56:50.522Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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