CVE-2026-43129

Description

In the Linux kernel, the following vulnerability has been resolved: ima: verify the previous kernel's IMA buffer lies in addressable RAM Patch series "Address page fault in ima_restore_measurement_list()", v3. When the second-stage kernel is booted via kexec with a limiting command line such as "mem=<size>" we observe a pafe fault that happens. BUG: unable to handle page fault for address: ffff97793ff47000 RIP: ima_restore_measurement_list+0xdc/0x45a #PF: error_code(0x0000) not-present page This happens on x86_64 only, as this is already fixed in aarch64 in commit: cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer against memory bounds") This patch (of 3): When the second-stage kernel is booted with a limiting command line (e.g. "mem=<size>"), the IMA measurement buffer handed over from the previous kernel may fall outside the addressable RAM of the new kernel. Accessing such a buffer can fault during early restore. Introduce a small generic helper, ima_validate_range(), which verifies that a physical [start, end] range for the previous-kernel IMA buffer lies within addressable memory: - On x86, use pfn_range_is_mapped(). - On OF based architectures, use page_is_ram().

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://git.kernel.org/stable/c/10d1c75ed4382a8e79874379caa2ead8952734f9
• https://git.kernel.org/stable/c/5366ec7d2f793ce703c403d7fd4c25a3db365b9d
• https://git.kernel.org/stable/c/9e1f51c1ad57cc76a0e8b5eb27038f8973fff4fa
• https://git.kernel.org/stable/c/f11d7d088f5ed54b31c6735854c12845eb60eb4a
• https://www.suse.com/security/cve/CVE-2026-43129.html
• https://security-tracker.debian.org/tracker/CVE-2026-43129
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-43129