CVE-2026-43112

#include <stdio.h> #include <string.h> #include <stdlib.h> // Simulated vulnerable logic based on the description char* cifs_sanitize_prepath_vulnerable(const char *path) { if (!path) return NULL; char *cursor = (char *)path; char *cursor2 = (char *)path; // Strip prepended delimiters while (*cursor == '/') { cursor++; } // Vulnerability: If input was only "/", cursor is at end (null terminator), // but cursor2 is still at the start. // The original logic checked *(cursor2 - 1) before cursor2 advanced. if (*cursor == '\0') { // This simulates the problematic check mentioned in the CVE description // checking *(cursor2 - 1) when cursor2 is at base address. char prev_char = *(cursor2 - 1); // Out-of-bounds read happens here printf("Read char before buffer: %c\n", prev_char); } return NULL; } int main() { // Trigger input: string containing only delimiters char *malicious_path = strdup("/"); printf("Testing CVE-2026-43112 PoC with input: '%s'\n", malicious_path); cifs_sanitize_prepath_vulnerable(malicious_path); free(malicious_path); return 0; }

{"cve": {"id": "CVE-2026-43112", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T10:16:24.927", "lastModified": "2026-05-08T19:43:23.620", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath\n\nWhen cifs_sanitize_prepath is called with an empty string or a string\ncontaining only delimiters (e.g., \"/\"), the current logic attempts to\ncheck *(cursor2 - 1) before cursor2 has advanced. This results in an\nout-of-bounds read.\n\nThis patch adds an early exit check after stripping prepended\ndelimiters. If no path content remains, the function returns NULL.\n\nThe bug was identified via manual audit and verified using a\nstandalone test case compiled with AddressSanitizer, which\ntriggered a SEGV on affected inputs."}], "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:R/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16.1", "versionEndExcluding": "6.6.136", "matchCriteriaId": "005FE1BE-809A-4536-BE37-C2437DE0927E"}, {"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:5.16:-:*:*:*:*:*:*", "matchCriteriaId": "FF588A58-013F-4DBF-A3AB-70EC054B1892"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc6:*:*:*:*:*:*", "matchCriteriaId": "8A0915FE-A4AA-4C94-B783-CF29D81E7E54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc7:*:*:*:*:*:*", "matchCriteriaId": "4EAC2750-F7C6-4A4E-9C04-1E450722B853"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc8:*:*:*:*:*:*", "matchCriteriaId": "ED611C74-E83A-4AFA-8688-9B829C02B038"}, {"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"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2d29214448ec0f4e7e18bb1c14dd4a6c07f1c439", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/49b1ce6d7cfb6c5a49f68bf5ccfcfb6ba14e63c3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5d4fe469fe7dbff7d874c196bb680a82f2625d95", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/78ec5bf2f589ec7fd8f169394bfeca541b077317", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/86f9c23e0814cfdffda9eedf0c591c51ba209010", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}