CVE-2026-43109

/* * PoC for CVE-2026-43109 * This code demonstrates the context of the vulnerability. * It attempts to trigger signal handling while manipulating memory mappings. * Note: Actual exploitation requires specific kernel version and hardware support (Shadow Stack). */ #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <unistd.h> #include <sys/mman.h> void handle_signal(int sig) { // Signal handler logic write(1, "Signal caught\n", 14); } int main() { // Register signal handler signal(SIGUSR1, handle_signal); printf("Starting PoC for CVE-2026-43109...\n"); // In a vulnerable kernel, we would need to ensure // shstk_pop_sigframe is called and mmap_read_lock_killable fails. // This usually involves a race condition or specific memory pressure. // Raise signal to trigger handler raise(SIGUSR1); return 0; }

{"cve": {"id": "CVE-2026-43109", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:24.577", "lastModified": "2026-05-17T16:16:16.517", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86: shadow stacks: proper error handling for mmap lock\n\n김영민 reports that shstk_pop_sigframe() doesn't check for errors from\nmmap_read_lock_killable(), which is a silly oversight, and also shows\nthat we haven't marked those functions with \"__must_check\", which would\nhave immediately caught it.\n\nSo let's fix both issues."}], "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": "6.6", "versionEndExcluding": "6.18.24", "matchCriteriaId": "1A24051D-1B64-47EB-A614-9D5B389080ED"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.14", "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB"}, {"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/1a30468eff661937d978495644d2e5ebfeef5ce6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/262b6d38a81d51b135db81e1f30c13d30e38feee", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/52f657e34d7b21b47434d9d8b26fa7f6778b63a0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c64cebcc5c4f223dbcbe7dcdf74908fc092a0aa4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c79cf42321600e931933e11f94aba8b245d4cd66", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}