{"id":"CVE-2024-26601","state":"PUBLISHED","title":"ext4: regenerate buddy after block freeing failed if under fc replay","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: regenerate buddy after block freeing failed if under fc replay\n\nThis mostly reverts commit 6bd97bf273bd (\"ext4: remove redundant\nmb_regenerate_buddy()\") and reintroduces mb_regenerate_buddy(). Based on\ncode in mb_free_blocks(), fast commit replay can end up marking as free\nblocks that are already marked as such. This causes corruption of the\nbuddy bitmap so we need to regenerate it in that case.","publishedAt":"2024-02-24T14:56:56.324Z","updatedAt":"2026-08-05T11:26:11.866Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"0983142c5f17a62055ec851372273c3bc77e4788","status":"affected","lessThan":"94ebf71bddbcd4ab1ce43ae32c6cb66396d2d51a","versionType":"git"},{"version":"6bd97bf273bdb4944904e57480f6545bca48ad77","status":"affected","lessThan":"c1317822e2de80e78f137d3a2d99febab1b80326","versionType":"git"},{"version":"6bd97bf273bdb4944904e57480f6545bca48ad77","status":"affected","lessThan":"78327acd4cdc4a1601af718b781eece577b6b7d4","versionType":"git"},{"version":"6bd97bf273bdb4944904e57480f6545bca48ad77","status":"affected","lessThan":"ea42d6cffb0dd27a417f410b9d0011e9859328cb","versionType":"git"},{"version":"6bd97bf273bdb4944904e57480f6545bca48ad77","status":"affected","lessThan":"6b0d48647935e4b8c7b75d1eccb9043fcd4ee581","versionType":"git"},{"version":"6bd97bf273bdb4944904e57480f6545bca48ad77","status":"affected","lessThan":"c9b528c35795b711331ed36dc3dbee90d5812d4e","versionType":"git"},{"version":"5.10.181","status":"affected","lessThan":"5.10.211","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mballoc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.11","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.11","versionType":"semver"},{"version":"5.10.211","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.150","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.78","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.17","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7.5","status":"unaffected","lessThanOrEqual":"6.7.*","versionType":"semver"},{"version":"6.8","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mballoc.c"]}],"references":["https://git.kernel.org/stable/c/94ebf71bddbcd4ab1ce43ae32c6cb66396d2d51a","https://git.kernel.org/stable/c/c1317822e2de80e78f137d3a2d99febab1b80326","https://git.kernel.org/stable/c/78327acd4cdc4a1601af718b781eece577b6b7d4","https://git.kernel.org/stable/c/ea42d6cffb0dd27a417f410b9d0011e9859328cb","https://git.kernel.org/stable/c/6b0d48647935e4b8c7b75d1eccb9043fcd4ee581","https://git.kernel.org/stable/c/c9b528c35795b711331ed36dc3dbee90d5812d4e","https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:07:10.607Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/26xxx/CVE-2024-26601.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-26601","state":"PUBLISHED","datePublished":"2024-02-24T14:56:56.324Z","dateUpdated":"2026-08-05T11:26:11.866Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-02-19T14:20:24.128Z"},"containers":{"cna":{"title":"ext4: regenerate buddy after block freeing failed if under fc replay","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: regenerate buddy after block freeing failed if under fc replay\n\nThis mostly reverts commit 6bd97bf273bd (\"ext4: remove redundant\nmb_regenerate_buddy()\") and reintroduces mb_regenerate_buddy(). 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There is no network-facing consumer of this path.\nAC:L - The attacker fully authors the filesystem image — fast-commit DEL_RANGE tags, extent trees and block bitmaps — so arranging a free of an already-free block is deterministic, with no race or memory-layout condition outside their control.\nPR:L - An unprivileged local user supplies the crafted ext4 image via removable media or a loop/user-mountable device; udisks2-style automounters and autofs perform the mount, and mounting in a user namespace also reaches this code without real root.\nUI:N - Automount daemons mount attacker-supplied removable media without any action by another user, and the fc replay runs unconditionally during that mount.\nS:U - The corruption is confined to ext4's in-kernel allocator metadata and the mounted filesystem; it stays within the kernel's own security authority with no VM/IOMMU boundary crossed.\nC:H - A group left with an inflated `bb_free` and a stale buddy is not quarantined, so mballoc can hand the attacker blocks whose true state it has lost track of, exposing residual on-disk contents of other files; the inconsistent metadata is also read back out of bounds of what the bitmap actually describes.\nI:H - The block allocator's authoritative accounting is left corrupt and the group stays in service, so subsequent allocations write through aliased/incorrectly-tracked blocks, corrupting other files' data and on-disk filesystem metadata.\nA:H - The desynchronized buddy reaches `BUG_ON`s in `mb_mark_used()` and `MB_CHECK_ASSERT()` in `mb_check_buddy()`, and the `ext4_grp_locked_error()` paths panic outright because the crafted image's `s_errors` field can select `errors=panic`; at minimum the filesystem is forced read-only."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:26:11.866Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.181","versionEndExcluding":"5.10.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.150"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.1.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.6.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.7.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.8"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-26601","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-03-01T15:48:58.021731Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-06-04T17:48:55.950Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/94ebf71bddbcd4ab1ce43ae32c6cb66396d2d51a","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/c1317822e2de80e78f137d3a2d99febab1b80326","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/78327acd4cdc4a1601af718b781eece577b6b7d4","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ea42d6cffb0dd27a417f410b9d0011e9859328cb","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/6b0d48647935e4b8c7b75d1eccb9043fcd4ee581","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/c9b528c35795b711331ed36dc3dbee90d5812d4e","tags":["x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T00:07:19.651Z"}}]}}}