# CVE-2026-15390: Out-of-bounds write in Das U-Boot

> An attacker can execute arbitrary code by sending fragmented IP packets to systems running Das U-Boot with IP defragmentation enabled.

- **Severity:** Critical 9.0 (`CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **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:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** AZL-105729, DEBIAN-CVE-2026-15390, GHSA-vm4x-pmjm-j3wm, UBUNTU-CVE-2026-15390

## What is CVE-2026-15390?

CVE-2026-15390 is a critical memory corruption vulnerability in DENX Software Engineering Das U-Boot, published on 29 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Das U-Boot with CONFIG_IP_DEFRAG=y parameter fails to clear IP reassembly state after delivering a complete datagram. An attacker who can deliver fragmented IP traffic can execute arbitrary code by sending duplicated last-fragment IP packets.

This issue was fixed in commit b1aec609bb5e0d08c25c888c91935287ab4ee5fa in version 2026.07.

Weakness: CWE-787 (Out-of-bounds Write), CWE-459 (Incomplete Cleanup)

## Which versions are affected by CVE-2026-15390?


## How do I fix CVE-2026-15390?

Apply the vendor's patch.

## Is CVE-2026-15390 being exploited?

There is no known exploitation of CVE-2026-15390 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15390 and fix it if it is affected.

What it is: CVE-2026-15390 is a critical memory corruption vulnerability in DENX Software Engineering Das U-Boot, published on 29 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-2026-15390 in the wild and no public exploit code.

Affected product: DENX Software Engineering Das U-Boot. 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-2026-15390/ (Markdown: https://insights.sbomify.com/CVE-2026-15390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15390
- OSV: https://osv.dev/vulnerability/CVE-2026-15390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15390/
Summaries are generated and may contain mistakes; the official description above is the record.