CVE-2026-43030: Linux Kernel BPF verifier incorrect state pruning in regsafe

CVE-2026-43030 · Severity: high · CVSS 7.8 · Published 2026-05-01

A vulnerability was identified in the Linux kernel's BPF verifier, a component responsible for ensuring that custom network and system programs run safely without crashing the operating system. Due to a logic error, the verifier might incorrectly approve a program that performs unsafe memory operations on network packets. If exploited, a local attacker could potentially gain unauthorized access to sensitive data or cause a complete system crash, impacting the reliability and security of the affected device.

Technologies: Linux Kernel, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP. Vendors: Linux, Siemens.

Quick answers

Is CVE-2026-43030 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-43030 being exploited in the wild.
How severe is CVE-2026-43030?
High severity, with a CVSS score of 7.8, published 1 May 2026.
Which products and versions are affected?
Linux Kernel 6d94e741a8ff to fixed versions; 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.
Is there a fix for CVE-2026-43030?
A patch was published on 2026-04-11: Commits merged into various stable kernel branches Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-43030 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-43030?
Check whether you run Linux Kernel, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability exists in the Linux kernel BPF verifier within the regsafe() function in kernel/bpf/verifier.c. The issue arises when comparing register states for packet pointers; specifically, if an old register state has a range marked as BEYOND_PKT_END while the current state has a different range, regsafe() may incorrectly return true. This causes the verifier to skip exploration of valid packet ranges, leading to incorrect state pruning. A local attacker with the ability to load BPF programs could exploit this to bypass verifier safety checks, potentially achieving arbitrary kernel memory access or a denial-of-service condition. The fix introduces explicit checks for special packet end markers to ensure states are not incorrectly considered equivalent.

Affected products

  • Linux Linux Kernel 6d94e741a8ff to fixed versions
  • 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

  • 2026-03-31: disclosed: Initial patch submitted by Alexei Starovoitov
  • 2026-04-11: patched: Commits merged into various stable kernel branches
  • 2026-05-01: advisory: CVE published

References

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