# CVE-2025-71266: fs: ntfs3: check return value of indx_find to avoid infinite loop

> A malformed NTFS3 filesystem image can cause an infinite loop and memory exhaustion in the Linux kernel, leading to a system crash.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 18 Mar 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-79989, BELL-CVE-2025-71266, DEBIAN-CVE-2025-71266, GHSA-f43g-cfgj-442p, ROOT-OS-DEBIAN-12-CVE-2025-71266, ROOT-OS-DEBIAN-13-CVE-2025-71266, ROOT-OS-UBUNTU-2204-CVE-2025-71266, ROOT-OS-UBUNTU-2404-CVE-2025-71266, UBUNTU-CVE-2025-71266

## What is CVE-2025-71266?

CVE-2025-71266 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Mar 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:

fs: ntfs3: check return value of indx_find to avoid infinite loop

We found an infinite loop bug in the ntfs3 file system that can lead to a
Denial-of-Service (DoS) condition.

A malformed dentry in the ntfs3 filesystem can cause the kernel to hang
during the lookup operations. By setting the HAS_SUB_NODE flag in an
INDEX_ENTRY within a directory's INDEX_ALLOCATION block and manipulating the
VCN pointer, an attacker can cause the indx_find() function to repeatedly
read the same block, allocating 4 KB of memory each time. The kernel lacks
VCN loop detection and depth limits, causing memory exhaustion and an OOM
crash.

This patch adds a return value check for fnd_push() to prevent a memory
exhaustion vulnerability caused by infinite loops. When the index exceeds the
size of the fnd->nodes array, fnd_push() returns -EINVAL. The indx_find()
function checks this return value and stops processing, preventing further
memory allocation.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2025-71266?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-71266?

Apply the vendor's patch.

## Is CVE-2025-71266 being exploited?

There is no known exploitation of CVE-2025-71266 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-71266 and fix it if it is affected.

What it is: CVE-2025-71266 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Mar 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-2025-71266 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-71266/ (Markdown: https://insights.sbomify.com/CVE-2025-71266/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-71266
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-71266
- OSV: https://osv.dev/vulnerability/CVE-2025-71266

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-71266/
Summaries are generated and may contain mistakes; the official description above is the record.