FKIE_CVE-2026-31457

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-04-23 16:17
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: check contexts->nr in repeat_call_fn damon_sysfs_repeat_call_fn() calls damon_sysfs_upd_tuned_intervals(), damon_sysfs_upd_schemes_stats(), and damon_sysfs_upd_schemes_effective_quotas() without checking contexts->nr. If nr_contexts is set to 0 via sysfs while DAMON is running, these functions dereference contexts_arr[0] and cause a NULL pointer dereference. Add the missing check. For example, the issue can be reproduced using DAMON sysfs interface and DAMON user-space tool (damo) [1] like below. $ sudo damo start --refresh_interval 1s $ echo 0 | sudo tee \ /sys/kernel/mm/damon/admin/kdamonds/0/contexts/nr_contexts
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3527e9fdc38570cea0f6ddb7a2c9303d4044b217
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/652cd0641a763dd0e846b0d12814977fadb2b7d8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6557004a8b59c7701e695f02be03c7e20ed1cc15
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts-\u003enr in repeat_call_fn\n\ndamon_sysfs_repeat_call_fn() calls damon_sysfs_upd_tuned_intervals(),\ndamon_sysfs_upd_schemes_stats(), and\ndamon_sysfs_upd_schemes_effective_quotas() without checking contexts-\u003enr. \nIf nr_contexts is set to 0 via sysfs while DAMON is running, these\nfunctions dereference contexts_arr[0] and cause a NULL pointer\ndereference.  Add the missing check.\n\nFor example, the issue can be reproduced using DAMON sysfs interface and\nDAMON user-space tool (damo) [1] like below.\n\n    $ sudo damo start --refresh_interval 1s\n    $ echo 0 | sudo tee \\\n            /sys/kernel/mm/damon/admin/kdamonds/0/contexts/nr_contexts"
    }
  ],
  "id": "CVE-2026-31457",
  "lastModified": "2026-04-23T16:17:41.280",
  "metrics": {},
  "published": "2026-04-22T14:16:41.133",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3527e9fdc38570cea0f6ddb7a2c9303d4044b217"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/652cd0641a763dd0e846b0d12814977fadb2b7d8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6557004a8b59c7701e695f02be03c7e20ed1cc15"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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