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Linux KernelOperating system · Linux

CVE-2022-49347

MEDIUM · 5.5 CVSS v3.1 Published 2025-02-26
Fix available
A fix is available. Upgrade to 4.9.318 / 4.14.283 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: ext4: fix bug_on in ext4_writepages we got issue as follows: EXT4-fs error (device loop0): ext4_mb_generate_buddy:1141: group 0, block bitmap and bg descriptor inconsistent: 25 vs 31513 free cls ------------[ cut here ]------------ kernel BUG at fs/ext4/inode.c:2708! invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 2 PID: 2147 Comm: rep Not tainted 5.18.0-rc2-next-20220413+ #155 RIP: 0010:ext4_writepages+0x1977/0x1c10 RSP: 0018:ffff88811d3e7880 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000 RDX: 0000000000000000 RSI: ffff88811c098000 RDI: 0000000000000002 RBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000 R10: 0000000000000007 R11: ffffed10250281ea R12: 0000000000000001 R13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028 FS: 00007f443aed9740(0000) GS:ffff8883aef00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> do_writepages+0x130/0x3a0 filemap_fdatawrite_wbc+0x83/0xa0 filemap_flush+0xab/0xe0 ext4_alloc_da_blocks+0x51/0x120 __ext4_ioctl+0x1534/0x3210 __x64_sys_ioctl+0x12c/0x170 do_syscall_64+0x3b/0x90 It may happen as follows: 1. write inline_data inode vfs_write new_sync_write ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin ext4_da_write_inline_data_begin -> If inline data size too small will allocate block to write, then mapping will has dirty page ext4_da_convert_inline_data_to_extent ->clear EXT4_STATE_MAY_INLINE_DATA 2. fallocate do_vfs_ioctl ioctl_preallocate vfs_fallocate ext4_fallocate ext4_convert_inline_data ext4_convert_inline_data_nolock ext4_map_blocks -> fail will goto restore data ext4_restore_inline_data ext4_create_inline_data ext4_write_inline_data ext4_set_inode_state -> set inode EXT4_STATE_MAY_INLINE_DATA 3. writepages __ext4_ioctl ext4_alloc_da_blocks filemap_flush filemap_fdatawrite_wbc do_writepages ext4_writepages if (ext4_has_inline_data(inode)) BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) The root cause of this issue is we destory inline data until call ext4_writepages under delay allocation mode. But there maybe already convert from inline to extent. To solve this issue, we call filemap_flush first..

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-617

Attacker-controllable input can reach an assertion that aborts the process when it fails, so a check meant for debugging becomes a denial-of-service in production. A single crafted request takes the service down. The fix is to handle unexpected input gracefully on reachable paths rather than asserting on it.

General guidance for the reachable assertion class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:< 4.9.318>= 4.10, < 4.14.283>= 4.15, < 4.19.247>= 4.20, < 5.4.198>= 5.5, < 5.10.121>= 5.11, < 5.15.46>= 5.16, < 5.17.14>= 5.18, < 5.18.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.9.318 / 4.14.283 / 4.19.247 or later
Fixed in 4.9.3184.14.2834.19.247
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel >= 4.9.318 (for 4.9.x), >= 4.14.283 (for 4.14.x), >= 4.19.247 (for 4.19.x), or >= 5.4.198 (for 5.4.x)

  1. Identify the currently running kernel version using `uname -r`
  2. Check if your distribution has released a kernel update that includes the fix (commit 013f12bdedb96816aaa27ee04349f4433d361f52)
  3. If a patched kernel is available from your distribution vendor, apply it via your package manager (e.g., `apt-get update && apt-get upgrade` for Debian/Ubuntu, `yum update` for RHEL/CentOS, or `dnf upgrade` for Fedora)
  4. Reboot the system to load the fixed kernel
  5. Verify the fix is applied by checking the kernel version matches or exceeds the fixed releases: 4.9.318, 4.14.283, 4.19.247, or 5.4.198 depending on your major version branch
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with third-party kernel modules; ensure backups and test in staging if possible

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-49347 in production — separate from our analysis above.

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