{"id":"CVE-2026-93795","state":"PUBLISHED","title":"blk-cgroup: fix leaks and online flag on radix_tree_insert failure","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: fix leaks and online flag on radix_tree_insert failure\n\nWhen radix_tree_insert() fails in blkg_create(), the error path has two\nissues:\n\n1. blkg->online is set to true unconditionally, even when the blkg was\n   never fully inserted.  Move the assignment inside the success block.\n\n2. The error path calls blkg_put() without first calling\n   percpu_ref_kill().  Because the refcount is still in percpu mode,\n   percpu_ref_put() only does this_cpu_sub() without checking for zero,\n   so blkg_release() is never triggered.  This permanently leaks the\n   blkg memory, its percpu iostat, policy data, the parent blkg\n   reference, and the cgroup css reference — the latter preventing the\n   cgroup from ever being destroyed.\n\nFix by replacing blkg_put() with percpu_ref_kill(), matching the pattern\nused in blkg_destroy().","publishedAt":"2026-09-24T16:02:28.654Z","updatedAt":"2026-10-03T10:57:30.314Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"0f840db042caee9d2f3dcdcf97d6674f6e4c1e30","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"f53945d7c712efe63fadbcc5ffed6370871fd0d3","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"ada8270ccdb6f212da5eb22614c28ea418746a4a","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"c3650be82ef6e7af13b79b2d10a7363bdf54aa7f","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"6e85f02d45b5977c0326a8d854c6db878aa6b34a","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"4c0d150fb98ea40760611979f4e664c244b20966","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"dbbca20764382b4d411ec2918f4e278ffe547acc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-cgroup.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-cgroup.c"]}],"references":["https://git.kernel.org/stable/c/0f840db042caee9d2f3dcdcf97d6674f6e4c1e30","https://git.kernel.org/stable/c/f53945d7c712efe63fadbcc5ffed6370871fd0d3","https://git.kernel.org/stable/c/ada8270ccdb6f212da5eb22614c28ea418746a4a","https://git.kernel.org/stable/c/c3650be82ef6e7af13b79b2d10a7363bdf54aa7f","https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a","https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966","https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93795.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93795","state":"PUBLISHED","datePublished":"2026-09-24T16:02:28.654Z","dateUpdated":"2026-10-03T10:57:30.314Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-18T17:59:28.789Z"},"containers":{"cna":{"title":"blk-cgroup: fix leaks and online flag on radix_tree_insert failure","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: fix leaks and online flag on radix_tree_insert failure\n\nWhen radix_tree_insert() fails in blkg_create(), the error path has two\nissues:\n\n1. blkg->online is set to true unconditionally, even when the blkg was\n   never fully inserted.  Move the assignment inside the success block.\n\n2. The error path calls blkg_put() without first calling\n   percpu_ref_kill().  Because the refcount is still in percpu mode,\n   percpu_ref_put() only does this_cpu_sub() without checking for zero,\n   so blkg_release() is never triggered.  This permanently leaks the\n   blkg memory, its percpu iostat, policy data, the parent blkg\n   reference, and the cgroup css reference — the latter preventing the\n   cgroup from ever being destroyed.\n\nFix by replacing blkg_put() with percpu_ref_kill(), matching the pattern\nused in blkg_destroy()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"0f840db042caee9d2f3dcdcf97d6674f6e4c1e30","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"f53945d7c712efe63fadbcc5ffed6370871fd0d3","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"ada8270ccdb6f212da5eb22614c28ea418746a4a","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"c3650be82ef6e7af13b79b2d10a7363bdf54aa7f","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"6e85f02d45b5977c0326a8d854c6db878aa6b34a","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"4c0d150fb98ea40760611979f4e664c244b20966","versionType":"git"},{"version":"7fcf2b033b84e261dca283bc2911aaea4b07b525","status":"affected","lessThan":"dbbca20764382b4d411ec2918f4e278ffe547acc","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-cgroup.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-cgroup.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0f840db042caee9d2f3dcdcf97d6674f6e4c1e30"},{"url":"https://git.kernel.org/stable/c/f53945d7c712efe63fadbcc5ffed6370871fd0d3"},{"url":"https://git.kernel.org/stable/c/ada8270ccdb6f212da5eb22614c28ea418746a4a"},{"url":"https://git.kernel.org/stable/c/c3650be82ef6e7af13b79b2d10a7363bdf54aa7f"},{"url":"https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a"},{"url":"https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966"},{"url":"https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-03T10:57:30.314Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}