CVE-2026-43308

/* * PoC for CVE-2026-43308 (Conceptual) * Triggering unexpected delayed ref type in btrfs. * Compile: gcc -o poc_btrfs poc_btrfs.c */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <linux/btrfs.h> int main(int argc, char *argv[]) { if (argc != 2) { printf("Usage: %s <mounted_btrfs_path>\n", argv[0]); return 1; } int fd = open(argv[1], O_RDONLY); if (fd < 0) { perror("open"); return 1; } // In a real exploitation scenario, specific ioctls or file system // operations are used to manipulate delayed refs to reach the // unexpected type condition in run_one_delayed_ref(). // This demonstrates the interface to interact with the filesystem. printf("Attempting to interact with btrfs volume at %s\n", argv[1]); // Logic to trigger the specific delayed ref state would go here. // This often involves creating snapshots, clones, or modifying // extents in a way that races or confuses the reference tracking. close(fd); printf("PoC executed. Check kernel logs for panic or BUG() messages.\n"); return 0; }

{"cve": {"id": "CVE-2026-43308", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T14:16:38.137", "lastModified": "2026-05-15T19:28:13.880", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: don't BUG() on unexpected delayed ref type in run_one_delayed_ref()\n\nThere is no need to BUG(), we can just return an error and log an error\nmessage."}], "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": "2.6.31", "versionEndExcluding": "6.19.6", "matchCriteriaId": "57E17887-BDEB-4BEC-B080-7B529B6EB8FC"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/5549743e11c06da23cfa7712a994b9f1e69064c6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/c7d1d4ff56744074e005771aff193b927392d51f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}