{"id":"CVE-2026-90277","state":"PUBLISHED","title":"md/md-llbitmap: prevent create failure bitmap UAF","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/md-llbitmap: prevent create failure bitmap UAF\n\nllbitmap_create() publishes mddev->bitmap before reading the bitmap\nsuperblock. This is needed because llbitmap_read_sb() can initialize a\nnew bitmap and flush it through helpers that use mddev->bitmap.\n\nIf llbitmap_read_sb() fails, the old cleanup dropped bitmap_info.mutex\nand freed llbitmap before clearing mddev->bitmap. Readers such as\n/proc/mdstat rely on bitmap_info.mutex to keep the bitmap pointer stable\nwhile collecting bitmap stats, so they could observe the stale pointer\nafter the failed create path released the mutex.\n\nClear mddev->bitmap while still holding bitmap_info.mutex, then free the\nfailed llbitmap after dropping the mutex. This makes mutex-protected\nreaders see either a live bitmap or no bitmap.","publishedAt":"2026-09-17T16:08:09.328Z","updatedAt":"2026-10-19T09:00:54.917Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"930cc4f1af5a1afcd545a6ba00e38921ff8401e0","versionType":"git"},{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"2f0722435ce3a844dbb66b9bb0a18229dcc8739c","versionType":"git"},{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"2116c2f0a0e547615886900e2ed8c529c016499b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/md-llbitmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.18","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/md-llbitmap.c"]}],"references":["https://git.kernel.org/stable/c/930cc4f1af5a1afcd545a6ba00e38921ff8401e0","https://git.kernel.org/stable/c/2f0722435ce3a844dbb66b9bb0a18229dcc8739c","https://git.kernel.org/stable/c/2116c2f0a0e547615886900e2ed8c529c016499b"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90277.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90277","state":"PUBLISHED","datePublished":"2026-09-17T16:08:09.328Z","dateUpdated":"2026-10-19T09:00:54.917Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.797Z"},"containers":{"cna":{"title":"md/md-llbitmap: prevent create failure bitmap UAF","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/md-llbitmap: prevent create failure bitmap UAF\n\nllbitmap_create() publishes mddev->bitmap before reading the bitmap\nsuperblock. This is needed because llbitmap_read_sb() can initialize a\nnew bitmap and flush it through helpers that use mddev->bitmap.\n\nIf llbitmap_read_sb() fails, the old cleanup dropped bitmap_info.mutex\nand freed llbitmap before clearing mddev->bitmap. Readers such as\n/proc/mdstat rely on bitmap_info.mutex to keep the bitmap pointer stable\nwhile collecting bitmap stats, so they could observe the stale pointer\nafter the failed create path released the mutex.\n\nClear mddev->bitmap while still holding bitmap_info.mutex, then free the\nfailed llbitmap after dropping the mutex. This makes mutex-protected\nreaders see either a live bitmap or no bitmap."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"930cc4f1af5a1afcd545a6ba00e38921ff8401e0","versionType":"git"},{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"2f0722435ce3a844dbb66b9bb0a18229dcc8739c","versionType":"git"},{"version":"5ab829f1971dc99f2aac10846c378e67fc875abc","status":"affected","lessThan":"2116c2f0a0e547615886900e2ed8c529c016499b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/md-llbitmap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.18","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/md-llbitmap.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/930cc4f1af5a1afcd545a6ba00e38921ff8401e0"},{"url":"https://git.kernel.org/stable/c/2f0722435ce3a844dbb66b9bb0a18229dcc8739c"},{"url":"https://git.kernel.org/stable/c/2116c2f0a0e547615886900e2ed8c529c016499b"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:00:54.917Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}