CVE-2026-31428

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD __build_packet_message() manually constructs the NFULA_PAYLOAD netlink attribute using skb_put() and skb_copy_bits(), bypassing the standard nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes are allocated (including NLA alignment padding), only data_len bytes of actual packet data are copied. The trailing nla_padlen(data_len) bytes (1-3 when data_len is not 4-byte aligned) are never initialized, leaking stale heap contents to userspace via the NFLOG netlink socket. Replace the manual attribute construction with nla_reserve(), which handles the tailroom check, header setup, and padding zeroing via __nla_reserve(). The subsequent skb_copy_bits() fills in the payload data on top of the properly initialized attribute.

CVSS 3.1

5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.1% chance of exploitation in the next 30 days; higher than 2% of CVEs (scores of 2026-10-25)

CWE

CWE-908

Published

2026-04-13

Modified

2026-10-15

Record from

the NVD, synced 2026-10-19

Affected

• linux:linux_kernel

References

• https://git.kernel.org/stable/c/21d8efda029948d3666b0db5afcc0d36c0984aae
• https://git.kernel.org/stable/c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7
• https://git.kernel.org/stable/c/7eff72968161fb8ddb26113344de3b92fb7d7ef5
• https://git.kernel.org/stable/c/7f3e5d72455936f42709116fabeca3bb216cda62
• https://git.kernel.org/stable/c/a2f6ff3444b663d6cfa63eadd61327a18592885a

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