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.
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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||||||||
| Linux | Linux | affected |
|
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| Vendors | Products |
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Linux
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 28 May 2026 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-200 CWE-665 |
Thu, 28 May 2026 10:15:00 +0000
| 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 |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-28T09:35:47.047Z
Reserved: 2026-05-13T15:03:33.099Z
Link: CVE-2026-46132
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2026-05-28T10:16:28.753
Modified: 2026-05-28T13:44:01.663
Link: CVE-2026-46132
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-05-28T13:30:15Z