# CVE-2026-97415: btrfs: tree-checker: validate names in ROOT_REF and ROOT_BACKREF

> A missing validation in the Linux kernel btrfs filesystem allows corrupted items to cause out-of-bounds reads, potentially leading to memory corruption or crashes.

- **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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103943, BELL-CVE-2026-97415, DEBIAN-CVE-2026-97415, GHSA-8vvp-6p8q-q9pq, UBUNTU-CVE-2026-97415

## What is CVE-2026-97415?

CVE-2026-97415 is a high-severity memory corruption vulnerability in Linux, published on 24 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:

btrfs: tree-checker: validate names in ROOT_REF and ROOT_BACKREF

ROOT_REF and ROOT_BACKREF items contain a struct btrfs_root_ref followed
by the subvolume name. Several readers assume that this layout is already
valid and then use the on-disk name length directly. A corrupted item can
therefore make those readers address bytes outside the item, and
BTRFS_IOC_GET_SUBVOL_INFO can copy too many bytes into its fixed-size UAPI
name buffer.

Validate ROOT_REF and ROOT_BACKREF items in tree-checker before any reader
uses them. Reject records that do not contain a non-empty name, whose
name_len does not exactly describe the remaining item payload, or whose
name exceeds BTRFS_NAME_LEN.

For BTRFS_IOC_GET_SUBVOL_INFO, copy only the validated on-disk name_len
instead of deriving the copy length from the item size. The ioctl result is
zeroed when allocated. That leaves the existing trailing zero byte
untouched.

## Which versions are affected by CVE-2026-97415?


## How do I fix CVE-2026-97415?

Apply the vendor's patch.

## Is CVE-2026-97415 being exploited?

There is no known exploitation of CVE-2026-97415 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97415 and fix it if it is affected.

What it is: CVE-2026-97415 is a high-severity memory corruption vulnerability in Linux, published on 24 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-2026-97415 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-2026-97415/ (Markdown: https://insights.sbomify.com/CVE-2026-97415/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97415
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97415
- OSV: https://osv.dev/vulnerability/CVE-2026-97415

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97415/
Summaries are generated and may contain mistakes; the official description above is the record.