Medium 5.5Published Apr 13, 2026

CVE-2026-31428netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

Updated under an hour ago (Oct 26, 2026, 6:00 PM ET)

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It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from df6fb868d6118686805c2fa566e213a8f31c8e4f before 7f3e5d72455936f42709116fabeca3bb216cda62; from df6fb868d6118686805c2fa566e213a8f31c8e4f before 21d8efda029948d3666b0db5afcc0d36c0984aae; from df6fb868d6118686805c2fa566e213a8f31c8e4f before fc961dd7272b5e4a462999635e44a4770d7f2482; from df6fb868d6118686805c2fa566e213a8f31c8e4f before a8365d1064ded323797c5e28e91070c52f44b76c; from df6fb868d6118686805c2fa566e213a8f31c8e4f before a2f6ff3444b663d6cfa63eadd61327a18592885a; from df6fb868d6118686805c2fa566e213a8f31c8e4f before c9f6c51d36482805ac3ffadb9663fe775a13e926; from df6fb868d6118686805c2fa566e213a8f31c8e4f before 7eff72968161fb8ddb26113344de3b92fb7d7ef5; from df6fb868d6118686805c2fa566e213a8f31c8e4f before 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.24 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.131; from 6.7 before 6.12.80; from 6.13 before 6.18.21; from 6.19 before 6.19.11; 7.0; and 4 more ranges	NVD

References

References

https://git.kernel.org/stable/c/7f3e5d72455936f42709116fabeca3bb216cda62	patch
https://git.kernel.org/stable/c/21d8efda029948d3666b0db5afcc0d36c0984aae	patch
https://git.kernel.org/stable/c/fc961dd7272b5e4a462999635e44a4770d7f2482	patch
https://git.kernel.org/stable/c/a8365d1064ded323797c5e28e91070c52f44b76c	patch
https://git.kernel.org/stable/c/a2f6ff3444b663d6cfa63eadd61327a18592885a	patch
https://git.kernel.org/stable/c/c9f6c51d36482805ac3ffadb9663fe775a13e926	patch
https://git.kernel.org/stable/c/7eff72968161fb8ddb26113344de3b92fb7d7ef5	patch
https://git.kernel.org/stable/c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.