{ "schema_version": "1.6.1", "id": "RPI-CVE-2024-26601", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2024-26601" ], "published": "2024-02-24T14:57:26Z", "summary": "ext4: regenerate buddy after block freeing failed if under fc replay", "details": "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.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.21-1+rpt1", "1:6.1.47-1+rpt2", "1:6.1.47-1+rpt4", "1:6.1.54-1+rpt2", "1:6.1.58-1+rpt2", "1:6.1.63-1+rpt1", "1:6.1.73-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi1-rpi-v6", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v7", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v8", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v6", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v7", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v7l", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v8", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-2712", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v6", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v7", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v7l", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v8", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-2712", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v6", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v7", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v7l", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v8", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-2712", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v6", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v7", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v7l", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v8", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-2712", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v6", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v7", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v7l", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v8", "binary_version": "1:6.1.73-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.1.21-1+rpt1": { "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed", "upstream_version": "6.1.21", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.78" }, "1:6.1.47-1+rpt2": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.78" }, "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.78", "compiled_filter": false }, "1:6.1.54-1+rpt2": { "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7", "upstream_version": "6.1.54", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.78" }, "1:6.1.58-1+rpt2": { "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18", "upstream_version": "6.1.58", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.78" }, "1:6.1.63-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.63", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.78" }, "1:6.1.73-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.73", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.78" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2024-26601" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/94ebf71bddbcd4ab1ce43ae32c6cb66396d2d51a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c1317822e2de80e78f137d3a2d99febab1b80326" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/78327acd4cdc4a1601af718b781eece577b6b7d4" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ea42d6cffb0dd27a417f410b9d0011e9859328cb" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6b0d48647935e4b8c7b75d1eccb9043fcd4ee581" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c9b528c35795b711331ed36dc3dbee90d5812d4e" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T11:52:36Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The vulnerable branch is only entered while `EXT4_FC_REPLAY` is set, i.e. during fast-commit journal recovery performed by the `mount()` syscall on a local block device or loop-mounted image. There is no network-facing consumer of this path.\nAC:L - The attacker fully authors the filesystem image \u2014 fast-commit DEL_RANGE tags, extent trees and block bitmaps \u2014 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." } } }