# CVE-2025-39835: xfs: do not propagate ENODATA disk errors into xattr code

> A null pointer dereference in the Linux kernel XFS filesystem can cause a system crash when disk errors are misinterpreted as missing attributes.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Sep 2025
- **Updated:** 12 May 2026
- **Also known as:** AZL-74736, BELL-CVE-2025-39835, DEBIAN-CVE-2025-39835, GHSA-x6rc-wf46-fv7m, ROOT-OS-DEBIAN-11-CVE-2025-39835, ROOT-OS-UBUNTU-2204-CVE-2025-39835, ROOT-OS-UBUNTU-2404-CVE-2025-39835, UBUNTU-CVE-2025-39835

## What is CVE-2025-39835?

CVE-2025-39835 is a high-severity vulnerability in Debian Debian Linux, published on 16 Sep 2025. 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:

xfs: do not propagate ENODATA disk errors into xattr code

ENODATA (aka ENOATTR) has a very specific meaning in the xfs xattr code;
namely, that the requested attribute name could not be found.

However, a medium error from disk may also return ENODATA. At best,
this medium error may escape to userspace as "attribute not found"
when in fact it's an IO (disk) error.

At worst, we may oops in xfs_attr_leaf_get() when we do:

	error = xfs_attr_leaf_hasname(args, &bp);
	if (error == -ENOATTR)  {
		xfs_trans_brelse(args->trans, bp);
		return error;
	}

because an ENODATA/ENOATTR error from disk leaves us with a null bp,
and the xfs_trans_brelse will then null-deref it.

As discussed on the list, we really need to modify the lower level
IO functions to trap all disk errors and ensure that we don't let
unique errors like this leak up into higher xfs functions - many
like this should be remapped to EIO.

However, this patch directly addresses a reported bug in the xattr
code, and should be safe to backport to stable kernels. A larger-scope
patch to handle more unique errors at lower levels can follow later.

(Note, prior to 07120f1abdff we did not oops, but we did return the
wrong error code to userspace.)

## Which versions are affected by CVE-2025-39835?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39835?

Apply the vendor's patch.

## Is CVE-2025-39835 being exploited?

There is no known exploitation of CVE-2025-39835 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39835 and fix it if it is affected.

What it is: CVE-2025-39835 is a high-severity vulnerability in Debian Debian Linux, published on 16 Sep 2025. 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-2025-39835 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-39835/ (Markdown: https://insights.sbomify.com/CVE-2025-39835/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39835
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39835
- OSV: https://osv.dev/vulnerability/CVE-2025-39835

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39835/
Summaries are generated and may contain mistakes; the official description above is the record.