In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: fix use-after-free in state_show() state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. This allows a use-after-free race: CPU 0 CPU 1 ----- ----- state_show() damon_sysfs_turn_damon_on() ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock); damon_destroy_ctx(kdamond->damon_ctx); kdamond->damon_ctx = NULL; mutex_unlock(&damon_sysfs_lock); damon_is_running(ctx); /* ctx is freed */ mutex_lock(&ctx->kdamond_lock); /* UAF */ (The race can also occur with damon_sysfs_kdamonds_rm_dirs() and damon_sysfs_kdamond_release(), which free or replace the context under damon_sysfs_lock.) Fix by taking damon_sysfs_lock before dereferencing the context, mirroring the locking used in pid_show(). The bug has existed since state_show() first accessed kdamond->damon_ctx.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00024.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

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Vendors Products
Linux
  • Linux Kernel
References
Link Providers
https://git.kernel.org/stable/c/26d29b2ac87a2989071755f9828ebf839b560d4c cve-icon cve-icon
https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff cve-icon cve-icon
https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e cve-icon cve-icon
https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58ce cve-icon cve-icon
https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025092301-CVE-2025-39877-1244@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-39877 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-39877 cve-icon
History

Wed, 24 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important

Tue, 23 Sep 2025 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Tue, 23 Sep 2025 06:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: fix use-after-free in state_show() state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. This allows a use-after-free race: CPU 0 CPU 1 ----- ----- state_show() damon_sysfs_turn_damon_on() ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock); damon_destroy_ctx(kdamond->damon_ctx); kdamond->damon_ctx = NULL; mutex_unlock(&damon_sysfs_lock); damon_is_running(ctx); /* ctx is freed */ mutex_lock(&ctx->kdamond_lock); /* UAF */ (The race can also occur with damon_sysfs_kdamonds_rm_dirs() and damon_sysfs_kdamond_release(), which free or replace the context under damon_sysfs_lock.) Fix by taking damon_sysfs_lock before dereferencing the context, mirroring the locking used in pid_show(). The bug has existed since state_show() first accessed kdamond->damon_ctx.
Title mm/damon/sysfs: fix use-after-free in state_show()
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-09-29T06:01:35.845Z

Reserved: 2025-04-16T07:20:57.144Z

Link: CVE-2025-39877

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-23T06:15:47.230

Modified: 2025-09-24T18:11:24.520

Link: CVE-2025-39877

cve-icon Redhat

Severity : Important

Publid Date: 2025-09-23T00:00:00Z

Links: CVE-2025-39877 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-09-23T16:03:14Z