# CVE-2025-70099: Null dereference in n/a

> Attackers can cause a denial of service in applications using lwext4 by providing a crafted EXT4 image that triggers a null pointer dereference.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Jun 2026
- **Updated:** 29 Jun 2026
- **Also known as:** GHSA-vgqp-ggfv-3xf6

## What is CVE-2025-70099?

CVE-2025-70099 is a high-severity vulnerability in n/a, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A NULL pointer dereference in the ext4_dir_en_get_name_len function in include/ext4_dir.h of lwext4 1.0.0 allows attackers to cause a denial of service by supplying a specially crafted EXT4 filesystem image with malformed directory entries. During directory iteration, the code may fail to validate the directory entry pointer before accessing the name_len field, resulting in a segmentation fault. This affects versions based on (or equivalent to) the 2016-era codebase (1.0.0).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-70099?


## How do I fix CVE-2025-70099?

No fix has been published for CVE-2025-70099 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-70099 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-70099 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-70099 and fix it if it is affected.

What it is: CVE-2025-70099 is a high-severity vulnerability in n/a, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-70099 exists.

Affected product: n/a. 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-2025-70099/ (Markdown: https://insights.sbomify.com/CVE-2025-70099/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-70099
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-70099
- OSV: https://osv.dev/vulnerability/CVE-2025-70099

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-70099/
Summaries are generated and may contain mistakes; the official description above is the record.