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CVE-2025-39877 (GCVE-0-2025-39877)

Vulnerability from cvelistv5 – Published: 2025-09-23 06:00 – Updated: 2026-05-11 21:38
VLAI
Title
mm/damon/sysfs: fix use-after-free in state_show()
Summary
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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a61ea561c87139992fe32afdee48a6f6b85d824a , < 3858c44341ad49dc7544b19cc9f9ecffaa7cc50e (git)
Affected: a61ea561c87139992fe32afdee48a6f6b85d824a , < 60d7a3d2b985a395318faa1d88da6915fad11c19 (git)
Affected: a61ea561c87139992fe32afdee48a6f6b85d824a , < 26d29b2ac87a2989071755f9828ebf839b560d4c (git)
Affected: a61ea561c87139992fe32afdee48a6f6b85d824a , < 4e87f461d61959647464a94d11ae15c011be58ce (git)
Affected: a61ea561c87139992fe32afdee48a6f6b85d824a , < 3260a3f0828e06f5f13fac69fb1999a6d60d9cff (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.18
Unaffected: 0 , < 5.18 (semver)
Unaffected: 6.1.153 , ≤ 6.1.* (semver)
Unaffected: 6.6.107 , ≤ 6.6.* (semver)
Unaffected: 6.12.48 , ≤ 6.12.* (semver)
Unaffected: 6.16.8 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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