FKIE_CVE-2025-39877

Vulnerability from fkie_nvd - Published: 2025-09-23 06:15 - Updated: 2026-01-20 20:29
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/26d29b2ac87a2989071755f9828ebf839b560d4cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cffPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50ePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58cePatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19Patch
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory, Mailing List
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
debian debian_linux 11.0
To clipboard 

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: fix use-after-free in state_show()\n\nstate_show() reads kdamond-\u003edamon_ctx without holding damon_sysfs_lock. \nThis allows a use-after-free race:\n\nCPU 0                         CPU 1\n-----                         -----\nstate_show()                  damon_sysfs_turn_damon_on()\nctx = kdamond-\u003edamon_ctx;     mutex_lock(\u0026damon_sysfs_lock);\n                              damon_destroy_ctx(kdamond-\u003edamon_ctx);\n                              kdamond-\u003edamon_ctx = NULL;\n                              mutex_unlock(\u0026damon_sysfs_lock);\ndamon_is_running(ctx);        /* ctx is freed */\nmutex_lock(\u0026ctx-\u003ekdamond_lock); /* UAF */\n\n(The race can also occur with damon_sysfs_kdamonds_rm_dirs() and\ndamon_sysfs_kdamond_release(), which free or replace the context under\ndamon_sysfs_lock.)\n\nFix by taking damon_sysfs_lock before dereferencing the context, mirroring\nthe locking used in pid_show().\n\nThe bug has existed since state_show() first accessed kdamond-\u003edamon_ctx."
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  "lastModified": "2026-01-20T20:29:36.387",
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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