{"api_version":"1","generated_at":"2026-08-16T16:28:00+00:00","cve":"CVE-2026-74571","urls":{"html":"https://cve.report/CVE-2026-74571","api":"https://cve.report/api/cve/CVE-2026-74571.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74571","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74571"},"summary":{"title":"btrfs: skip global block reserve accounting for rescue mounts","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: skip global block reserve accounting for rescue mounts\n\n[BUG]\nMounting with rescue=ibadroots after corrupting the block group tree\nroot triggers a NULL pointer dereference:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000100\n  RIP: 0010:btrfs_update_global_block_rsv+0x9d/0x1c0 [btrfs]\n  Call Trace:\n   fill_dummy_bgs+0xd4/0x120 [btrfs]\n   open_ctree+0xc6e/0x1ca0 [btrfs]\n   btrfs_get_tree+0x50d/0xa40 [btrfs]\n\nThe same crash occurs with a corrupted raid stripe tree root, via\nbtrfs_read_block_groups() instead of fill_dummy_bgs().\n\n[CAUSE]\nWith rescue=ibadroots, btrfs_read_roots() allows the mount to continue\nwhen either root cannot be read, leaving the corresponding root pointer\nNULL while its on-disk feature bit remains set.\n\nbtrfs_update_global_block_rsv() then dereferences the missing root based\non the feature bit alone.\n\n[FIX]\nRescue mounts are fully read-only and cannot start transactions, so the\nglobal reserve is never consumed. Under btrfs_is_full_ro(), mark the\nreserve as full and return before performing the accounting.\n\nAnd since we need to check if the fs is mount fully RO, export\nfs_is_full_ro() as btrfs_is_full_ro(), and move it to fs.h.\n\n[ Squash the fs_is_full_ro() export commit into this one. ]","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:18:02","updated_at":"2026-08-15 13:18:02"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/076349e4c8d11f6b58c4549976a513b2b4dc6df2","name":"https://git.kernel.org/stable/c/076349e4c8d11f6b58c4549976a513b2b4dc6df2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/51a0e8399858621442807a26057bcd1cd3ced046","name":"https://git.kernel.org/stable/c/51a0e8399858621442807a26057bcd1cd3ced046","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74571","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74571","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8dbfc14fc736eb701089aff09645c3d4ad3decb1 076349e4c8d11f6b58c4549976a513b2b4dc6df2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8dbfc14fc736eb701089aff09645c3d4ad3decb1 51a0e8399858621442807a26057bcd1cd3ced046 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cbec34d3021d47007a0334c634f7053dbaf93d02 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1e8087589b5cf6fa17adaf57b64cf1656d77dfec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.1.43 6.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.4.8 6.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.5","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc6 * 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":["fs/btrfs/block-rsv.c","fs/btrfs/disk-io.c","fs/btrfs/fs.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"076349e4c8d11f6b58c4549976a513b2b4dc6df2","status":"affected","version":"8dbfc14fc736eb701089aff09645c3d4ad3decb1","versionType":"git"},{"lessThan":"51a0e8399858621442807a26057bcd1cd3ced046","status":"affected","version":"8dbfc14fc736eb701089aff09645c3d4ad3decb1","versionType":"git"},{"status":"affected","version":"cbec34d3021d47007a0334c634f7053dbaf93d02","versionType":"git"},{"status":"affected","version":"1e8087589b5cf6fa17adaf57b64cf1656d77dfec","versionType":"git"},{"lessThan":"6.2","status":"affected","version":"6.1.43","versionType":"semver"},{"lessThan":"6.5","status":"affected","version":"6.4.8","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/btrfs/block-rsv.c","fs/btrfs/disk-io.c","fs/btrfs/fs.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.5"},{"lessThan":"6.5","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc6","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.8","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc6","versionStartIncluding":"6.5","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.43","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: skip global block reserve accounting for rescue mounts\n\n[BUG]\nMounting with rescue=ibadroots after corrupting the block group tree\nroot triggers a NULL pointer dereference:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000100\n  RIP: 0010:btrfs_update_global_block_rsv+0x9d/0x1c0 [btrfs]\n  Call Trace:\n   fill_dummy_bgs+0xd4/0x120 [btrfs]\n   open_ctree+0xc6e/0x1ca0 [btrfs]\n   btrfs_get_tree+0x50d/0xa40 [btrfs]\n\nThe same crash occurs with a corrupted raid stripe tree root, via\nbtrfs_read_block_groups() instead of fill_dummy_bgs().\n\n[CAUSE]\nWith rescue=ibadroots, btrfs_read_roots() allows the mount to continue\nwhen either root cannot be read, leaving the corresponding root pointer\nNULL while its on-disk feature bit remains set.\n\nbtrfs_update_global_block_rsv() then dereferences the missing root based\non the feature bit alone.\n\n[FIX]\nRescue mounts are fully read-only and cannot start transactions, so the\nglobal reserve is never consumed. Under btrfs_is_full_ro(), mark the\nreserve as full and return before performing the accounting.\n\nAnd since we need to check if the fs is mount fully RO, export\nfs_is_full_ro() as btrfs_is_full_ro(), and move it to fs.h.\n\n[ Squash the fs_is_full_ro() export commit into this one. ]"}],"providerMetadata":{"dateUpdated":"2026-08-15T12:28:10.711Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/076349e4c8d11f6b58c4549976a513b2b4dc6df2"},{"url":"https://git.kernel.org/stable/c/51a0e8399858621442807a26057bcd1cd3ced046"}],"title":"btrfs: skip global block reserve accounting for rescue mounts","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74571","datePublished":"2026-08-15T12:28:10.711Z","dateReserved":"2026-08-15T05:44:03.917Z","dateUpdated":"2026-08-15T12:28:10.711Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:18:02","lastModifiedDate":"2026-08-15 13:18:02","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74571","Ordinal":"1","Title":"btrfs: skip global block reserve accounting for rescue mounts","CVE":"CVE-2026-74571","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74571","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: skip global block reserve accounting for rescue mounts\n\n[BUG]\nMounting with rescue=ibadroots after corrupting the block group tree\nroot triggers a NULL pointer dereference:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000100\n  RIP: 0010:btrfs_update_global_block_rsv+0x9d/0x1c0 [btrfs]\n  Call Trace:\n   fill_dummy_bgs+0xd4/0x120 [btrfs]\n   open_ctree+0xc6e/0x1ca0 [btrfs]\n   btrfs_get_tree+0x50d/0xa40 [btrfs]\n\nThe same crash occurs with a corrupted raid stripe tree root, via\nbtrfs_read_block_groups() instead of fill_dummy_bgs().\n\n[CAUSE]\nWith rescue=ibadroots, btrfs_read_roots() allows the mount to continue\nwhen either root cannot be read, leaving the corresponding root pointer\nNULL while its on-disk feature bit remains set.\n\nbtrfs_update_global_block_rsv() then dereferences the missing root based\non the feature bit alone.\n\n[FIX]\nRescue mounts are fully read-only and cannot start transactions, so the\nglobal reserve is never consumed. Under btrfs_is_full_ro(), mark the\nreserve as full and return before performing the accounting.\n\nAnd since we need to check if the fs is mount fully RO, export\nfs_is_full_ro() as btrfs_is_full_ro(), and move it to fs.h.\n\n[ Squash the fs_is_full_ro() export commit into this one. ]","Type":"Description","Title":"btrfs: skip global block reserve accounting for rescue mounts"}]}}}