VulnerabilityPublished 28 May 2026Updated 6 Nov 2026

CVE-2026-46132: Linux kernel · net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fbe0e6197225e6a83cf113a67a4b425f8de0bcd5 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:34 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in fbe0e6197225e6a83cf113a67a4b425f8de0bcd5, cccce3190ba4356432b9f22369b56123d3d89f0d, c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 28 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < fbe0e6197225e6a83cf113a67a4b425f8de0bcd5	Fixed in fbe0e6197225e6a83cf113a67a4b425f8de0bcd5
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < cccce3190ba4356432b9f22369b56123d3d89f0d	Fixed in cccce3190ba4356432b9f22369b56123d3d89f0d
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8	Fixed in c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < a44fbb631cba646532f3948636626f81717365a7	Fixed in a44fbb631cba646532f3948636626f81717365a7
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < 14271b401ec6a4bf0d88054106fc2956084717e1	Fixed in 14271b401ec6a4bf0d88054106fc2956084717e1
LinuxLinux	Affected ≥ 75345f888f700c4ab2448287e35d48c760b202e6, < 0653c0516234c8258975d268a749115fc0f0ff00	Fixed in 0653c0516234c8258975d268a749115fc0f0ff00

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.

References

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