CVE-2026-31458 (GCVE-0-2026-31458)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-04-22 13:53
VLAI?
Title
mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]
Summary
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().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 , < aba546061341b56e9ffb37e1eb661a3628b6ec12 (git)
Affected: 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 , < 1e8da792672481d603fa7cd0d815577220a3ee27 (git)
Affected: 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 , < 708033c231bd782858f4ddbb46ee874a5a5fbdab (git)
Affected: 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 , < bbe03ad3fb9e714191757ca7b41582f930be7be2 (git)
Affected: 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 , < 1bfe9fb5ed2667fb075682408b776b5273162615 (git)
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    Linux Linux Affected: 5.18
Unaffected: 0 , < 5.18 (semver)
Unaffected: 6.6.131 , ≤ 6.6.* (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts-\u003enr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond-\u003econtexts-\u003enr == 1.  A user can set nr_contexts to\n0 via sysfs while DAMON is running, causing NULL pointer dereferences.\n\nIn more detail, the issue can be triggered by privileged users like\nbelow.\n\nFirst, start DAMON and make contexts directory empty\n(kdamond-\u003econtexts-\u003enr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 \u003e contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats \u003e state\n    # echo update_schemes_tried_regions \u003e state\n    # echo update_schemes_tried_bytes \u003e state\n    # echo update_schemes_effective_quotas \u003e state\n    # echo update_tuned_intervals \u003e state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd()."
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    "dateReserved": "2026-03-09T15:48:24.092Z",
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}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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