{"api_version":"1","generated_at":"2026-04-23T08:15:24+00:00","cve":"CVE-2026-31458","urls":{"html":"https://cve.report/CVE-2026-31458","api":"https://cve.report/api/cve/CVE-2026-31458.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31458","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31458"},"summary":{"title":"mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond->contexts->nr == 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->contexts->nr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats > state\n    # echo update_schemes_tried_regions > state\n    # echo update_schemes_tried_bytes > state\n    # echo update_schemes_effective_quotas > state\n    # echo update_tuned_intervals > state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-04-22 14:16:41","updated_at":"2026-04-22 14:16:41"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab","name":"https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615","name":"https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12","name":"https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27","name":"https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2","name":"https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31458","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31458","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 aba546061341b56e9ffb37e1eb661a3628b6ec12 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 1e8da792672481d603fa7cd0d815577220a3ee27 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 708033c231bd782858f4ddbb46ee874a5a5fbdab git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 bbe03ad3fb9e714191757ca7b41582f930be7be2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ac32b8affb5a384253dbb8339bd2d0e91add0b7 1bfe9fb5ed2667fb075682408b776b5273162615 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.131 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.80 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.21 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.11 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/damon/sysfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"aba546061341b56e9ffb37e1eb661a3628b6ec12","status":"affected","version":"0ac32b8affb5a384253dbb8339bd2d0e91add0b7","versionType":"git"},{"lessThan":"1e8da792672481d603fa7cd0d815577220a3ee27","status":"affected","version":"0ac32b8affb5a384253dbb8339bd2d0e91add0b7","versionType":"git"},{"lessThan":"708033c231bd782858f4ddbb46ee874a5a5fbdab","status":"affected","version":"0ac32b8affb5a384253dbb8339bd2d0e91add0b7","versionType":"git"},{"lessThan":"bbe03ad3fb9e714191757ca7b41582f930be7be2","status":"affected","version":"0ac32b8affb5a384253dbb8339bd2d0e91add0b7","versionType":"git"},{"lessThan":"1bfe9fb5ed2667fb075682408b776b5273162615","status":"affected","version":"0ac32b8affb5a384253dbb8339bd2d0e91add0b7","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/damon/sysfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.18"},{"lessThan":"5.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.131","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.80","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.21","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.131","versionStartIncluding":"5.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.80","versionStartIncluding":"5.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.21","versionStartIncluding":"5.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.11","versionStartIncluding":"5.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"5.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond->contexts->nr == 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->contexts->nr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats > state\n    # echo update_schemes_tried_regions > state\n    # echo update_schemes_tried_bytes > state\n    # echo update_schemes_effective_quotas > state\n    # echo update_tuned_intervals > state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd()."}],"providerMetadata":{"dateUpdated":"2026-04-22T13:53:50.883Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12"},{"url":"https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27"},{"url":"https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab"},{"url":"https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2"},{"url":"https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615"}],"title":"mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-31458","datePublished":"2026-04-22T13:53:50.883Z","dateReserved":"2026-03-09T15:48:24.092Z","dateUpdated":"2026-04-22T13:53:50.883Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-04-22 14:16:41","lastModifiedDate":"2026-04-22 14:16:41","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"31458","Ordinal":"1","Title":"mm/damon/sysfs: check contexts->nr before accessing contexts_arr","CVE":"CVE-2026-31458","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31458","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond->contexts->nr == 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->contexts->nr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats > state\n    # echo update_schemes_tried_regions > state\n    # echo update_schemes_tried_bytes > state\n    # echo update_schemes_effective_quotas > state\n    # echo update_tuned_intervals > state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd().","Type":"Description","Title":"mm/damon/sysfs: check contexts->nr before accessing contexts_arr"}]}}}