CVE-2025-39877

7.8 HIGH
Published: September 23, 2025 Modified: January 20, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://git.kernel.org/stable/c/26d29b2ac87a2989071755f9828ebf839b560d4c
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58ce
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory Mailing List

6 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.8 / 10.0
EPSS (Exploit Probability)
0.0%
3th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

linux debian