# CVE-2026-13351: net: Maliciously fragmented IPv6 packets can prevent receiving/processing future incoming packets

> Attackers can cause denial of service in Zephyr RTOS by sending malicious fragmented IPv6 packets that exhaust network buffers.

- **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:** 25 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-cv4q-2j56-4wqf

## What is CVE-2026-13351?

CVE-2026-13351 is a high-severity denial of service vulnerability in Zephyrproject Zephyr, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Zephyr's IPv6 network stack can be prevented from receiving or processing future incoming packets by sending a small number of maliciously fragmented IPv6 packets. When such a packet is handled by the fragment-header processing path, the associated RX network packet buffer (allocated from a memory slab) is not released back to the pool. Repeating the malicious packet exhausts all RX buffer slots, after which the device can no longer obtain RX buffers and stops receiving traffic, resulting in a denial of service.

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2026-13351?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-13351?

No fix has been published for CVE-2026-13351 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13351 being exploited?

There is no known exploitation of CVE-2026-13351 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13351 and fix it if it is affected.

What it is: CVE-2026-13351 is a high-severity denial of service vulnerability in Zephyrproject Zephyr, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13351 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. 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-2026-13351/ (Markdown: https://insights.sbomify.com/CVE-2026-13351/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13351
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13351
- OSV: https://osv.dev/vulnerability/CVE-2026-13351

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-13351/
Summaries are generated and may contain mistakes; the official description above is the record.