netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

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Summary

CVECVE-2026-31428
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-13 14:16:12 UTC
Updated2026-07-14 13:18:40 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

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

EPSS: 0.000320000 probability, percentile 0.092520000 (date 2026-04-21)

Problem Types: CWE-908

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f 7f3e5d72455936f42709116fabeca3bb216cda62 git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f 21d8efda029948d3666b0db5afcc0d36c0984aae git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f fc961dd7272b5e4a462999635e44a4770d7f2482 git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f a8365d1064ded323797c5e28e91070c52f44b76c git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f a2f6ff3444b663d6cfa63eadd61327a18592885a git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f c9f6c51d36482805ac3ffadb9663fe775a13e926 git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f 7eff72968161fb8ddb26113344de3b92fb7d7ef5 git Not specified
CNA Linux Linux affected df6fb868d6118686805c2fa566e213a8f31c8e4f 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7 git Not specified
CNA Linux Linux affected 2.6.24 Not specified
CNA Linux Linux unaffected 2.6.24 semver Not specified
CNA Linux Linux unaffected 5.10.253 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.203 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.168 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.131 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.80 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.21 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.11 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/a2f6ff3444b663d6cfa63eadd61327a18592885a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/a8365d1064ded323797c5e28e91070c52f44b76c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-082556.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
cert-portal.siemens.com/productcert/html/ssa-019113.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/21d8efda029948d3666b0db5afcc0d36c0984aae 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7f3e5d72455936f42709116fabeca3bb216cda62 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/c9f6c51d36482805ac3ffadb9663fe775a13e926 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/fc961dd7272b5e4a462999635e44a4770d7f2482 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7eff72968161fb8ddb26113344de3b92fb7d7ef5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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