Linux Kernel up to 6.19.10 netfilter __build_packet_message uninitialized pointer

CVSS Meta Temp Score
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CTI Interest Score
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5.4$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10. The impacted element is the function __build_packet_message of the component netfilter. The manipulation leads to uninitialized pointer. This vulnerability is referenced as CVE-2026-31428. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.167/6.6.130/6.12.79/6.18.20/6.19.10. It has been rated as critical. This issue affects the function __build_packet_message of the component netfilter. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. Using CWE to declare the problem leads to CWE-824. The product accesses or uses a pointer that has not been initialized. The impact remains unknown. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-31428 since 03/09/2026. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/18/2026).

The vulnerability scanner Nessus provides a plugin with the ID 313522 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.168, 6.6.131, 6.12.80, 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch fc961dd7272b5e4a462999635e44a4770d7f2482/a8365d1064ded323797c5e28e91070c52f44b76c/a2f6ff3444b663d6cfa63eadd61327a18592885a/c9f6c51d36482805ac3ffadb9663fe775a13e926/7eff72968161fb8ddb26113344de3b92fb7d7ef5/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (313522), EUVD (EUVD-2026-21957) and CERT Bund (WID-SEC-2026-1088). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Uninitialized pointer
CWE: CWE-824 / CWE-908
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 313522
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1681)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.168/6.6.131/6.12.80/6.18.21/6.19.11
Patch: fc961dd7272b5e4a462999635e44a4770d7f2482/a8365d1064ded323797c5e28e91070c52f44b76c/a2f6ff3444b663d6cfa63eadd61327a18592885a/c9f6c51d36482805ac3ffadb9663fe775a13e926/7eff72968161fb8ddb26113344de3b92fb7d7ef5/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7

Timelineinfo

03/09/2026 CVE reserved
04/13/2026 +34 days Advisory disclosed
04/13/2026 +0 days VulDB entry created
06/18/2026 +66 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31428 (🔒)
GCVE (CVE): GCVE-0-2026-31428
GCVE (VulDB): GCVE-100-357155
EUVD: 🔒
CERT Bund: WID-SEC-2026-1088 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/13/2026 16:06
Updated: 06/18/2026 16:09
Changes: 04/13/2026 16:06 (59), 04/13/2026 17:58 (1), 05/10/2026 05:45 (2), 05/21/2026 01:09 (10), 06/18/2026 16:09 (7)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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