ghsa-46f8-9r54-mw7h
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2025-39877"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-23T06:15:47Z",
"severity": null
},
"details": "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.",
"id": "GHSA-46f8-9r54-mw7h",
"modified": "2025-09-23T06:30:27Z",
"published": "2025-09-23T06:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39877"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/26d29b2ac87a2989071755f9828ebf839b560d4c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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