CVE-2026-31753

Description

In the Linux kernel, the following vulnerability has been resolved: auxdisplay: line-display: fix NULL dereference in linedisp_release linedisp_release() currently retrieves the enclosing struct linedisp via to_linedisp(). That lookup depends on the attachment list, but the attachment may already have been removed before put_device() invokes the release callback. This can happen in linedisp_unregister(), and can also be reached from some linedisp_register() error paths. In that case, to_linedisp() returns NULL and linedisp_release() dereferences it while freeing the display resources. The struct device released here is the embedded linedisp->dev used by linedisp_register(), so retrieve the enclosing object directly with container_of() instead.

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

cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* - VULNERABLE

Linux Kernel (修复Commit 625fdac4前)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * Conceptual Trigger for CVE-2026-31753
 * This snippet demonstrates the kernel flow leading to the crash.
 * Requires kernel context to execute.
 */

#include <linux/module.h>
#include <linux/device.h>

// Simulating the race condition where put_device is called
// after attachment list is modified.
void simulate_linedisp_unregister_race() {
    struct device *dev = get_mock_device();
    
    // 1. Attachment is removed (e.g., in linedisp_unregister)
    // list_del(&linedisp->attachments);

    // 2. put_device triggers release callback
    // put_device(&linedisp->dev);

    // 3. Inside linedisp_release (Vulnerable code)
    // struct linedisp *ld = to_linedisp(dev); // Returns NULL
    // kfree(ld->buffer); // CRASH: NULL pointer dereference
}

int init_module(void) {
    // Trigger logic here
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-31753
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-31753
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-31753/
[4] VulDB https://vuldb.com/cve/CVE-2026-31753
[5] https://git.kernel.org/stable/c/625fdac41cfc4ca9e1774a0d31d7985aec2c1d66
[6] https://git.kernel.org/stable/c/7f138de156b20d9f9da6f72f90b63c01941d97d3

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-31753", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:38.223", "lastModified": "2026-05-08T18:52:16.810", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nauxdisplay: line-display: fix NULL dereference in linedisp_release\n\nlinedisp_release() currently retrieves the enclosing struct linedisp via\nto_linedisp(). That lookup depends on the attachment list, but the\nattachment may already have been removed before put_device() invokes the\nrelease callback. This can happen in linedisp_unregister(), and can also\nbe reached from some linedisp_register() error paths.\n\nIn that case, to_linedisp() returns NULL and linedisp_release()\ndereferences it while freeing the display resources.\n\nThe struct device released here is the embedded linedisp->dev used by\nlinedisp_register(), so retrieve the enclosing object directly with\ncontainer_of() instead."}], "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-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"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/625fdac41cfc4ca9e1774a0d31d7985aec2c1d66", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7f138de156b20d9f9da6f72f90b63c01941d97d3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}