Staging Environment: Content and features may be unstable or change without notice.
Search for vulnerabilities
Vulnerability details: VCID-3821-uy1e-sqcm
Vulnerability ID VCID-3821-uy1e-sqcm
Aliases CVE-2024-26944
Summary In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix use-after-free in do_zone_finish() Shinichiro reported the following use-after-free triggered by the device replace operation in fstests btrfs/070. BTRFS info (device nullb1): scrub: finished on devid 1 with status: 0 ================================================================== BUG: KASAN: slab-use-after-free in do_zone_finish+0x91a/0xb90 [btrfs] Read of size 8 at addr ffff8881543c8060 by task btrfs-cleaner/3494007 CPU: 0 PID: 3494007 Comm: btrfs-cleaner Tainted: G W 6.8.0-rc5-kts #1 Hardware name: Supermicro Super Server/X11SPi-TF, BIOS 3.3 02/21/2020 Call Trace: <TASK> dump_stack_lvl+0x5b/0x90 print_report+0xcf/0x670 ? __virt_addr_valid+0x200/0x3e0 kasan_report+0xd8/0x110 ? do_zone_finish+0x91a/0xb90 [btrfs] ? do_zone_finish+0x91a/0xb90 [btrfs] do_zone_finish+0x91a/0xb90 [btrfs] btrfs_delete_unused_bgs+0x5e1/0x1750 [btrfs] ? __pfx_btrfs_delete_unused_bgs+0x10/0x10 [btrfs] ? btrfs_put_root+0x2d/0x220 [btrfs] ? btrfs_clean_one_deleted_snapshot+0x299/0x430 [btrfs] cleaner_kthread+0x21e/0x380 [btrfs] ? __pfx_cleaner_kthread+0x10/0x10 [btrfs] kthread+0x2e3/0x3c0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> Allocated by task 3493983: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 btrfs_alloc_device+0xb3/0x4e0 [btrfs] device_list_add.constprop.0+0x993/0x1630 [btrfs] btrfs_scan_one_device+0x219/0x3d0 [btrfs] btrfs_control_ioctl+0x26e/0x310 [btrfs] __x64_sys_ioctl+0x134/0x1b0 do_syscall_64+0x99/0x190 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Freed by task 3494056: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3f/0x60 poison_slab_object+0x102/0x170 __kasan_slab_free+0x32/0x70 kfree+0x11b/0x320 btrfs_rm_dev_replace_free_srcdev+0xca/0x280 [btrfs] btrfs_dev_replace_finishing+0xd7e/0x14f0 [btrfs] btrfs_dev_replace_by_ioctl+0x1286/0x25a0 [btrfs] btrfs_ioctl+0xb27/0x57d0 [btrfs] __x64_sys_ioctl+0x134/0x1b0 do_syscall_64+0x99/0x190 entry_SYSCALL_64_after_hwframe+0x6e/0x76 The buggy address belongs to the object at ffff8881543c8000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 96 bytes inside of freed 1024-byte region [ffff8881543c8000, ffff8881543c8400) The buggy address belongs to the physical page: page:00000000fe2c1285 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1543c8 head:00000000fe2c1285 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x17ffffc0000840(slab|head|node=0|zone=2|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 0017ffffc0000840 ffff888100042dc0 ffffea0019e8f200 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881543c7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8881543c7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8881543c8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881543c8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881543c8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb This UAF happens because we're accessing stale zone information of a already removed btrfs_device in do_zone_finish(). The sequence of events is as follows: btrfs_dev_replace_start btrfs_scrub_dev btrfs_dev_replace_finishing btrfs_dev_replace_update_device_in_mapping_tree <-- devices replaced btrfs_rm_dev_replace_free_srcdev btrfs_free_device <-- device freed cleaner_kthread btrfs_delete_unused_bgs btrfs_zone_finish do_zone_finish <-- refers the freed device The reason for this is that we're using a ---truncated---
Status Published
Exploitability 0.5
Weighted Severity 5.0
Risk 2.5
Affected and Fixed Packages Package Details
Weaknesses (0)
There are no known CWE.
System Score Found at
cvssv3 5.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2024-26944.json
epss 0.00012 https://api.first.org/data/v1/epss?cve=CVE-2024-26944
epss 0.00012 https://api.first.org/data/v1/epss?cve=CVE-2024-26944
cvssv3.1 6.4 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
ssvc Track https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302
ssvc Track https://git.kernel.org/stable/c/34ca809e055eca5cfe63d9c7efbf80b7c21b4e57
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2024-26944.json
https://api.first.org/data/v1/epss?cve=CVE-2024-26944
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
1ec17ef59168a1a6f1105f5dc517f783839a5302 https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302
2278210 https://bugzilla.redhat.com/show_bug.cgi?id=2278210
34ca809e055eca5cfe63d9c7efbf80b7c21b4e57 https://git.kernel.org/stable/c/34ca809e055eca5cfe63d9c7efbf80b7c21b4e57
USN-6816-1 https://usn.ubuntu.com/6816-1/
USN-6817-1 https://usn.ubuntu.com/6817-1/
USN-6817-2 https://usn.ubuntu.com/6817-2/
USN-6817-3 https://usn.ubuntu.com/6817-3/
USN-6878-1 https://usn.ubuntu.com/6878-1/
No exploits are available.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2024-26944.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-05-28T17:52:17Z/ Found at https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2024-05-28T17:52:17Z/ Found at https://git.kernel.org/stable/c/34ca809e055eca5cfe63d9c7efbf80b7c21b4e57
Exploit Prediction Scoring System (EPSS)
Percentile 0.0161
EPSS Score 0.00012
Published At June 5, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:50:08.840604+00:00 Debian Importer Import https://security-tracker.debian.org/tracker/data/json 38.6.0