# CVE-2026-80806: ext4: don't enable DAX on new encrypted files

> Attackers can bypass encryption on new ext4 files if DAX is enabled, allowing unauthorized access to plaintext data.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-99669, BELL-CVE-2026-80806, DEBIAN-CVE-2026-80806, GHSA-jqxc-3f8r-hc2f, UBUNTU-CVE-2026-80806

## What is CVE-2026-80806?

CVE-2026-80806 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ext4: don't enable DAX on new encrypted files

Currently, when a new encrypted regular file is created, the call to
ext4_set_inode_flags(inode, init=true) in __ext4_new_inode() is made
before EXT4_INODE_ENCRYPT is set.  As a result, it can set S_DAX if the
filesystem is mounted with "-o dax=always".

EXT4_INODE_ENCRYPT then actually gets set a bit later in
__ext4_new_inode(), when it calls fscrypt_set_context() which calls
ext4_set_context().  ext4_set_context() sets EXT4_INODE_ENCRYPT and
calls ext4_set_inode_flags(inode, init=false) to set S_ENCRYPTED too.

This was intended to clear S_DAX as well.  However, this was broken by
commit 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load").  This
causes data written to the file to bypass encryption, also causing
xfstests failures such as generic/548 (when "-o dax=always" is used).

Fix this by simplifying the flow by making __ext4_new_inode() set
EXT4_INODE_ENCRYPT earlier.  This makes it take effect in
ext4_set_inode_flags(inode, init=true), making S_DAX never be set.

Similarly, make EXT4_STATE_MAY_INLINE_DATA never be set in the first
place on new encrypted inodes.  Then it doesn't need to be cleared.

As a result of these simplifications, ext4_set_context() no longer needs
to change inode flags or state when 'handle != NULL'.  Remove that too.

## Which versions are affected by CVE-2026-80806?


## How do I fix CVE-2026-80806?

Apply the vendor's patch.

## Is CVE-2026-80806 being exploited?

There is no known exploitation of CVE-2026-80806 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80806 and fix it if it is affected.

What it is: CVE-2026-80806 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80806 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80806/ (Markdown: https://insights.sbomify.com/CVE-2026-80806/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80806
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80806
- OSV: https://osv.dev/vulnerability/CVE-2026-80806

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80806/
Summaries are generated and may contain mistakes; the official description above is the record.