--- id: CVE-2026-46132 title: >- 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 initialisa… 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 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: 0.00166 epssPercentile: 0.05204 ingestedAt: '2026-09-08T13:33:24.578Z' --- ## Overview 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. ## 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` ## Remediation Upgrade past the affected range: - `linux_kernel 7.0.7` ## Vendor advisories - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46132.json)