csirt@kutim:~/threat-intel/cve/CVE-2021-47508

Katalog CVE

CVSS 5.5 · Medium EPSS 0,21%

Kerentanan Missing Release of Memory after Effective Lifetime pada linux kernel. Skor CVSS 3.1 5.5 (Medium) menurut NVD.

Deskripsi (NVD)

In the Linux kernel, the following vulnerability has been resolved: btrfs: free exchange changeset on failures Fstests runs on my VMs have show several kmemleak reports like the following. unreferenced object 0xffff88811ae59080 (size 64): comm "xfs_io", pid 12124, jiffies 4294987392 (age 6.368s) hex dump (first 32 bytes): 00 c0 1c 00 00 00 00 00 ff cf 1c 00 00 00 00 00 ................ 90 97 e5 1a 81 88 ff ff 90 97 e5 1a 81 88 ff ff ................ backtrace: [<00000000ac0176d2>] ulist_add_merge+0x60/0x150 [btrfs] [<0000000076e9f312>] set_state_bits+0x86/0xc0 [btrfs] [<0000000014fe73d6>] set_extent_bit+0x270/0x690 [btrfs] [<000000004f675208>] set_record_extent_bits+0x19/0x20 [btrfs] [<00000000b96137b1>] qgroup_reserve_data+0x274/0x310 [btrfs] [<0000000057e9dcbb>] btrfs_check_data_free_space+0x5c/0xa0 [btrfs] [<0000000019c4511d>] btrfs_delalloc_reserve_space+0x1b/0xa0 [btrfs] [<000000006d37e007>] btrfs_dio_iomap_begin+0x415/0x970 [btrfs] [<00000000fb8a74b8>] iomap_iter+0x161/0x1e0 [<0000000071dff6ff>] __iomap_dio_rw+0x1df/0x700 [<000000002567ba53>] iomap_dio_rw+0x5/0x20 [<0000000072e555f8>] btrfs_file_write_iter+0x290/0x530 [btrfs] [<000000005eb3d845>] new_sync_write+0x106/0x180 [<000000003fb505bf>] vfs_write+0x24d/0x2f0 [<000000009bb57d37>] __x64_sys_pwrite64+0x69/0xa0 [<000000003eba3fdf>] do_syscall_64+0x43/0x90 In case brtfs_qgroup_reserve_data() or btrfs_delalloc_reserve_metadata() fail the allocated extent_changeset will not be freed. So in btrfs_check_data_free_space() and btrfs_delalloc_reserve_space() free the allocated extent_changeset to get rid of the allocated memory. The issue currently only happens in the direct IO write path, but only after 65b3c08606e5 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range"), and also at defrag_one_locked_target(). Every other place is always calling extent_changeset_free() even if its call to btrfs_delalloc_reserve_space() or btrfs_check_data_free_space() has failed.

Rincian

Terbit di NVD
24 Mei 2024
Terakhir diubah
17 Juni 2026
Status NVD
Analyzed
CVSS 3.1
5.5 (Medium), sumber NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-401: Missing Release of Memory after Effective Lifetime
EPSS (30 hari)
0,21% peluang dieksploitasi; lebih tinggi dari 9,7% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
linux linux kernel Semua versi sebelum 5.15.8
linux linux kernel Versi 5.16 rc1
linux linux kernel Versi 5.16 rc2
linux linux kernel Versi 5.16 rc3
linux linux kernel Versi 5.16 rc4

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

Sumber: NVD · CVE.org · EPSS. Halaman ini disusun otomatis dari data tersebut; pembaruan terakhir 5 Okt 2026, 20:10 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.