# CVE-2026-108952: RT-Thread through 5.3.0 Memory Corruption via USB CDC VCOM Driver

> A memory corruption flaw in the RT-Thread USB CDC driver allows a connected host to cause denial of service via buffer overflow and invalid free.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-x4hq-c3c6-m368

## What is CVE-2026-108952?

CVE-2026-108952 is a medium-severity memory corruption vulnerability in rt-thread, published on 12 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

RT-Thread through 5.3.0 contains a memory corruption vulnerability in the legacy USB CDC virtual COM port driver that aliases rx_ringbuffer as a Serial V2 rt_serial_rx_fifo in _function_enable(). A connected USB host configuring the CDC device triggers writes past the ring buffer into struct vcom members and an invalid rt_free() on close, causing denial of service.

Weakness: CWE-843 (Access of Resource Using Incompatible Type)

## Which versions are affected by CVE-2026-108952?


## How do I fix CVE-2026-108952?

No fix has been published for CVE-2026-108952 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-108952 being exploited?

There is no known exploitation of CVE-2026-108952 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-108952 and fix it if it is affected.

What it is: CVE-2026-108952 is a medium-severity memory corruption vulnerability in rt-thread, published on 12 Oct 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-2026-108952 in the wild and no public exploit code.

Affected product: rt-thread. 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-2026-108952/ (Markdown: https://insights.sbomify.com/CVE-2026-108952/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-108952
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-108952
- OSV: https://osv.dev/vulnerability/CVE-2026-108952

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-108952/
Summaries are generated and may contain mistakes; the official description above is the record.