userfaultfd: fix a race between writeprotect and exit_mmap()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2021-47461
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-05-22 07:15:11 UTC
Updated2026-08-04 10:17:04 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a race between writeprotect and exit_mmap() A race is possible when a process exits, its VMAs are removed by exit_mmap() and at the same time userfaultfd_writeprotect() is called. The race was detected by KASAN on a development kernel, but it appears to be possible on vanilla kernels as well. Use mmget_not_zero() to prevent the race as done in other userfaultfd operations.

Risk And Classification

Primary CVSS: v3.1 4.7 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-362

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary4.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03 3cda4bfffd4f755645577aaa9e96a606657b4525 git Not specified
CNA Linux Linux affected 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03 149958ecd0627a9f1e9c678c25c665400054cd6a git Not specified
CNA Linux Linux affected 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03 cb185d5f1ebf900f4ae3bf84cee212e6dd035aca git Not specified
CNA Linux Linux affected 5.7 Not specified
CNA Linux Linux unaffected 5.7 semver Not specified
CNA Linux Linux unaffected 5.10.76 5.10.* semver Not specified
CNA Linux Linux unaffected 5.14.15 5.14.* semver Not specified
CNA Linux Linux unaffected 5.15 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/3cda4bfffd4f755645577aaa9e96a606657b4525 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/149958ecd0627a9f1e9c678c25c665400054cd6a af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/cb185d5f1ebf900f4ae3bf84cee212e6dd035aca af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
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