CVE-2026-46132 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00
https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011
https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0
https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8
https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5

Type	Values Removed	Values Added
Description		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.
Title		net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00 https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011 https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0 https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8 https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-46132", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.099Z", "datePublished": "2026-05-28T09:35:47.047Z", "dateUpdated": "2026-05-28T09:35:47.047Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-28T09:35:47.047Z"}, "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->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."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/core/rtnetlink.c"], "versions": [{"version": "75345f888f700c4ab2448287e35d48c760b202e6", "lessThan": "0653c0516234c8258975d268a749115fc0f0ff00", "status": "affected", "versionType": "git"}, {"version": "75345f888f700c4ab2448287e35d48c760b202e6", "lessThan": "c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8", "status": "affected", "versionType": "git"}, {"version": "75345f888f700c4ab2448287e35d48c760b202e6", "lessThan": "fbe0e6197225e6a83cf113a67a4b425f8de0bcd5", "status": "affected", "versionType": "git"}, {"version": "75345f888f700c4ab2448287e35d48c760b202e6", "lessThan": "38bcc21f52246badb3154b6158dcb381d98de011", "status": "affected", "versionType": "git"}, {"version": "75345f888f700c4ab2448287e35d48c760b202e6", "lessThan": "4b9e327991815e128ad3af75c3a04630a63ce3e0", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/core/rtnetlink.c"], "versions": [{"version": "5.3", "status": "affected"}, {"version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.88", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.30", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.7", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1-rc3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.6.140"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.12.88"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.18.30"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.0.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.1-rc3"}]}]}], "references": [{"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"}}}}

{"cveTags": [], "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->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."}], "id": "CVE-2026-46132", "lastModified": "2026-05-28T10:16:28.753", "metrics": {}, "published": "2026-05-28T10:16:28.753", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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