CVE-2022-49080

mm/mempolicy: fix mpol_new leak in shared_policy_replace

Published Feb 26, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

mm/mempolicy: fix mpol_new leak in shared_policy_replace

If mpol_new is allocated but not used in restart loop, mpol_new will be
freed via mpol_put before returning to the caller. But refcnt is not
initialized yet, so mpol_put could not do the right things and might
leak the unused mpol_new. This would happen if mempolicy was updated on
the shared shmem file while the sp->lock has been dropped during the
memory allocation.

This issue could be triggered easily with the below code snippet if
there are many processes doing the below work at the same time:

shmid = shmget((key_t)5566, 1024 * PAGE_SIZE, 0666|IPC_CREAT);
shm = shmat(shmid, 0, 0);
loop many times {
mbind(shm, 1024 * PAGE_SIZE, MPOL_LOCAL, mask, maxnode, 0);
mbind(shm + 128 * PAGE_SIZE, 128 * PAGE_SIZE, MPOL_DEFAULT, mask,
maxnode, 0);
}

Analysis

No analysis available yet

Remediation

No remediation available yet

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2022-55124 In the Linux kernel, the following vulnerability has been resolved: mm/mempolicy: fix mpol_new leak in shared_policy_replace If mpol_new is allocated but not used in restart loop, mpol_new will be freed via mpol_put before returning to the caller. But refcnt is not initialized yet, so mpol_put could not do the right things and might leak the unused mpol_new. This would happen if mempolicy was updated on the shared shmem file while the sp->lock has been dropped during the memory allocation. This issue could be triggered easily with the below code snippet if there are many processes doing the below work at the same time: shmid = shmget((key_t)5566, 1024 * PAGE_SIZE, 0666|IPC_CREAT); shm = shmat(shmid, 0, 0); loop many times { mbind(shm, 1024 * PAGE_SIZE, MPOL_LOCAL, mask, maxnode, 0); mbind(shm + 128 * PAGE_SIZE, 128 * PAGE_SIZE, MPOL_DEFAULT, mask, maxnode, 0); }
History
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:3.8:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.18:rc1:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Type Values Removed Values Added
Metrics epss

{'score': 0.0008}

epss

{'score': 0.0003}

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Type Values Removed Values Added
Weaknesses CWE-401
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/mempolicy: fix mpol_new leak in shared_policy_replace If mpol_new is allocated but not used in restart loop, mpol_new will be freed via mpol_put before returning to the caller. But refcnt is not initialized yet, so mpol_put could not do the right things and might leak the unused mpol_new. This would happen if mempolicy was updated on the shared shmem file while the sp->lock has been dropped during the memory allocation. This issue could be triggered easily with the below code snippet if there are many processes doing the below work at the same time: shmid = shmget((key_t)5566, 1024 * PAGE_SIZE, 0666|IPC_CREAT); shm = shmat(shmid, 0, 0); loop many times { mbind(shm, 1024 * PAGE_SIZE, MPOL_LOCAL, mask, maxnode, 0); mbind(shm + 128 * PAGE_SIZE, 128 * PAGE_SIZE, MPOL_DEFAULT, mask, maxnode, 0); }
Title mm/mempolicy: fix mpol_new leak in shared_policy_replace
References
Weaknesses
  • CWE-401

    Missing Release of Memory after Effective Lifetime

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 6:52 PM
Reserved
Feb 26, 2025, 1:49 AM
Status
Analyzed
Published
Feb 26, 2025, 7:00 AM
Modified
Jun 17, 2026, 5:17 AM
Severity
Moderate
Public date
Feb 26, 2025, 12:00 AM