{"id":"CVE-2026-46132","title":"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 initialisa…","summary":"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 initialisa…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-908"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.3, < 5.10.258","linux_kernel >= 5.11, < 5.15.209","linux_kernel >= 5.16, < 6.1.175","linux_kernel >= 6.2, < 6.6.140","linux_kernel >= 6.7, < 6.12.88","linux_kernel >= 6.13, < 6.18.30","linux_kernel >= 6.19, < 7.0.7","linux_kernel = 7.1"],"patched":["linux_kernel 7.0.7"],"published":"2026-05-28","updated":"2026-09-08","sourceUpdated":"2026-09-08T09:18:08.247","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-46132","references":[{"url":"https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/14271b401ec6a4bf0d88054106fc2956084717e1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a44fbb631cba646532f3948636626f81717365a7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cccce3190ba4356432b9f22369b56123d3d89f0d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46132.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-46132"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2482536"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-46132"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46132"},{"url":"https://lore.kernel.org/linux-cve-announce/2026052817-CVE-2026-46132-9410@gregkh/T"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00131,"epssPercentile":0.03071,"ingestedAt":"2026-09-08T13:33:24.578Z","slug":"CVE-2026-46132","body":"## Overview\n\nIn 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->broadcast into it using dev->addr_len\nas the length:\n\n\tmemcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);\n\nOn Ethernet devices (the overwhelming majority of SR-IOV NICs)\ndev->addr_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), &vf_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.\n\n## Affected\n\n- `linux_kernel >= 5.3, < 5.10.258`\n- `linux_kernel >= 5.11, < 5.15.209`\n- `linux_kernel >= 5.16, < 6.1.175`\n- `linux_kernel >= 6.2, < 6.6.140`\n- `linux_kernel >= 6.7, < 6.12.88`\n- `linux_kernel >= 6.13, < 6.18.30`\n- `linux_kernel >= 6.19, < 7.0.7`\n- `linux_kernel = 7.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.7`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46132.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}