Junglewise Threat Intelligence

CVE-2026-43028: Linux Kernel Netfilter missing null-termination in x_tables

CVE-2026-43028 · Severity: high · CVSS 7.1 · Published 2026-05-01

Executive brief

A vulnerability exists in the Linux kernel's networking subsystem (Netfilter) which is used for firewalling and traffic filtering. An attacker with local access to the system could provide specially crafted input that lacks proper termination, potentially leading to system instability or unauthorized access to sensitive kernel memory. This issue also affects certain Siemens industrial controllers that utilize the Linux kernel.

Technical details

A vulnerability in the Netfilter x_tables component of the Linux kernel arises from a failure to validate that string inputs (such as cgroup paths or rate estimator names) are null-terminated before they are passed to functions expecting C-style strings. Specifically, the 'xt_cgroup' and 'xt_rateest' modules were found to be vulnerable. A local attacker can exploit this by providing a name that lacks a null terminator, causing the kernel to read past the intended buffer. This can result in a kernel information leak or a denial-of-service (system crash). The fix involves adding 'strnlen' checks to ensure names are properly terminated within their allocated buffer size.

Affected products

  • Linux Linux Kernel Fixed in 6.7.12, 6.8.3, and other stable branches via backports
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5, V3.1.6
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5, V3.1.6
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5, V3.1.6

Timeline

  • 2026-05-01: disclosed
  • 2026-04-01: patched: Initial patch in Linux kernel mainline
  • 2026-05-01: advisory

References

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