Description
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0] Multiple sysfs command paths dereference contexts_arr[0] without first verifying that kdamond->contexts->nr == 1. A user can set nr_contexts to 0 via sysfs while DAMON is running, causing NULL pointer dereferences. In more detail, the issue can be triggered by privileged users like below. First, start DAMON and make contexts directory empty (kdamond->contexts->nr == 0). # damo start # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/nr_contexts Then, each of below commands will cause the NULL pointer dereference. # echo update_schemes_stats > state # echo update_schemes_tried_regions > state # echo update_schemes_tried_bytes > state # echo update_schemes_effective_quotas > state # echo update_tuned_intervals > state Guard all commands (except OFF) at the entry point of damon_sysfs_handle_cmd().
Affected products
linux: linux kernel
References5
- git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615 Patch
- git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27 Patch
- git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab Patch
- git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12 Patch
- git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2 Patch
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 2 · as of 13 November 2026
- CWE
- CWE-476
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