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CVE-2022-50021— ext4: block range must be validated before use in ext4_mb_clear_bb()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ext4_mb_clear_bb函数中未验证块范围。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.20% · P10

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 84130193e0e6568dfdfb823f0e1e19aec80aff6e< 7550aade978371ac582f6d43b14c4cb89ca54463 affected
84130193e0e6568dfdfb823f0e1e19aec80aff6e< 560a2744cbbf03cac65a6394f9b0d99aa437c867 affected
84130193e0e6568dfdfb823f0e1e19aec80aff6e< a2522041d248a8c969cbbc97e1fc2cd8b4de120d affected
84130193e0e6568dfdfb823f0e1e19aec80aff6e< 1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6 affected
3.2 affected
< 3.2 unaffected
5.10.175≤ 5.10.* unaffected
5.15.103≤ 5.15.* unaffected
… +2 more rows
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I. Basic Information for CVE-2022-50021

Vulnerability Information
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Vulnerability Title
ext4: block range must be validated before use in ext4_mb_clear_bb()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ext4: block range must be validated before use in ext4_mb_clear_bb() Block range to free is validated in ext4_free_blocks() using ext4_inode_block_valid() and then it's passed to ext4_mb_clear_bb(). However in some situations on bigalloc file system the range might be adjusted after the validation in ext4_free_blocks() which can lead to troubles on corrupted file systems such as one found by syzkaller that resulted in the following BUG kernel BUG at fs/ext4/ext4.h:3319! PREEMPT SMP NOPTI CPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014 RIP: 0010:ext4_free_blocks+0x95e/0xa90 Call Trace: <TASK> ? lock_timer_base+0x61/0x80 ? __es_remove_extent+0x5a/0x760 ? __mod_timer+0x256/0x380 ? ext4_ind_truncate_ensure_credits+0x90/0x220 ext4_clear_blocks+0x107/0x1b0 ext4_free_data+0x15b/0x170 ext4_ind_truncate+0x214/0x2c0 ? _raw_spin_unlock+0x15/0x30 ? ext4_discard_preallocations+0x15a/0x410 ? ext4_journal_check_start+0xe/0x90 ? __ext4_journal_start_sb+0x2f/0x110 ext4_truncate+0x1b5/0x460 ? __ext4_journal_start_sb+0x2f/0x110 ext4_evict_inode+0x2b4/0x6f0 evict+0xd0/0x1d0 ext4_enable_quotas+0x11f/0x1f0 ext4_orphan_cleanup+0x3de/0x430 ? proc_create_seq_private+0x43/0x50 ext4_fill_super+0x295f/0x3ae0 ? snprintf+0x39/0x40 ? sget_fc+0x19c/0x330 ? ext4_reconfigure+0x850/0x850 get_tree_bdev+0x16d/0x260 vfs_get_tree+0x25/0xb0 path_mount+0x431/0xa70 __x64_sys_mount+0xe2/0x120 do_syscall_64+0x5b/0x80 ? do_user_addr_fault+0x1e2/0x670 ? exc_page_fault+0x70/0x170 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fdf4e512ace Fix it by making sure that the block range is properly validated before used every time it changes in ext4_free_blocks() or ext4_mb_clear_bb().
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ext4_mb_clear_bb函数中未验证块范围。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 84130193e0e6568dfdfb823f0e1e19aec80aff6e ~ 7550aade978371ac582f6d43b14c4cb89ca54463 -
Linux Linux 3.2 -

II. Public POCs for CVE-2022-50021

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III. Intelligence Information for CVE-2022-50021

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Same Patch Batch · Linux · 2025-06-18 · 362 CVEs total

CVE-2025-38075 9.8 CRITICAL scsi: target: iscsi: Fix timeout on deleted connection
CVE-2022-50098 8.8 HIGH scsi: qla2xxx: Fix crash due to stale SRB access around I/O timeouts
CVE-2025-38052 8.8 HIGH net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done
CVE-2022-49934 8.8 HIGH wifi: mac80211: Fix UAF in ieee80211_scan_rx()
CVE-2022-50164 8.8 HIGH wifi: iwlwifi: mvm: fix double list_add at iwl_mvm_mac_wake_tx_queue
CVE-2025-38016 8.8 HIGH HID: bpf: abort dispatch if device destroyed
CVE-2025-38074 8.8 HIGH vhost-scsi: protect vq->log_used with vq->mutex
CVE-2022-49974 8.8 HIGH HID: nintendo: fix rumble worker null pointer deref
CVE-2022-49968 8.0 HIGH ieee802154/adf7242: defer destroy_workqueue call
CVE-2022-50028 7.8 HIGH gadgetfs: ep_io - wait until IRQ finishes
CVE-2022-49950 7.8 HIGH misc: fastrpc: fix memory corruption on open
CVE-2022-49939 7.8 HIGH binder: fix UAF of ref->proc caused by race condition
CVE-2022-49935 7.8 HIGH dma-buf/dma-resv: check if the new fence is really later
CVE-2025-38082 7.8 HIGH gpio: virtuser: fix potential out-of-bound write
CVE-2022-50182 7.8 HIGH media: imx-jpeg: Align upwards buffer size
CVE-2025-38080 7.8 HIGH drm/amd/display: Increase block_sequence array size
CVE-2025-38079 7.8 HIGH crypto: algif_hash - fix double free in hash_accept
CVE-2025-38060 7.8 HIGH bpf: copy_verifier_state() should copy 'loop_entry' field
CVE-2025-38062 7.8 HIGH genirq/msi: Store the IOMMU IOVA directly in msi_desc instead of iommu_cookie
CVE-2022-50101 7.8 HIGH video: fbdev: vt8623fb: Check the size of screen before memset_io()

Showing top 20 of 362 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2022-50021

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