NuytsTech Security

CVE-2026-31457

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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

More information : https://git.kernel.org/stable/c/3527e9fdc38570cea0f6ddb7a2c9303d4044b217

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