CVE-2026-31428

Description

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.

PUBLISHED Reserved 2026-03-09 | Published 2026-04-13 | Updated 2026-05-11 | Assigner Linux

Product status

References

git.kernel.org/...c/7f3e5d72455936f42709116fabeca3bb216cda62

git.kernel.org/...c/21d8efda029948d3666b0db5afcc0d36c0984aae

git.kernel.org/...c/fc961dd7272b5e4a462999635e44a4770d7f2482

git.kernel.org/...c/a8365d1064ded323797c5e28e91070c52f44b76c

git.kernel.org/...c/a2f6ff3444b663d6cfa63eadd61327a18592885a

git.kernel.org/...c/c9f6c51d36482805ac3ffadb9663fe775a13e926

git.kernel.org/...c/7eff72968161fb8ddb26113344de3b92fb7d7ef5

git.kernel.org/...c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7

cve.org (CVE-2026-31428)

nvd.nist.gov (CVE-2026-31428)

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