# CVE-2025-5867: RT-Thread lwp_syscall.c csys_sendto null pointer dereference

> A null pointer dereference in RT-Thread's csys_sendto function allows attackers to cause a denial of service.

- **Severity:** High 8.6 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X`)
- **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:** No
- **Published:** 9 Jun 2025
- **Updated:** 9 Jun 2025
- **Also known as:** GHSA-mq4q-q9rw-jvph

## What is CVE-2025-5867?

CVE-2025-5867 is a high-severity vulnerability in RT-Thread, published on 9 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability classified as critical was found in RT-Thread 5.1.0. This vulnerability affects the function csys_sendto of the file rt-thread/components/lwp/lwp_syscall.c. The manipulation of the argument to leads to null pointer dereference.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2025-5867?

It affects 1 product.


Products: Rt-Thread Rt-Thread.

## How do I fix CVE-2025-5867?

No fix has been published for CVE-2025-5867 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-5867 being exploited?

There is no known exploitation of CVE-2025-5867 in the wild and no public exploit code.

## Other vulnerabilities in RT-Thread

- [CVE-2024-25393](https://insights.sbomify.com/CVE-2024-25393/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-25395](https://insights.sbomify.com/CVE-2024-25395/): Memory corruption in n/a (high 8.8)
- [CVE-2025-5865](https://insights.sbomify.com/CVE-2025-5865/): RT-Thread Parameter lwp_syscall.c sys_select memory corruption (high 8.6)
- [CVE-2025-5866](https://insights.sbomify.com/CVE-2025-5866/): RT-Thread lwp_syscall.c sys_sigprocmask array index (high 8.6)
- [CVE-2025-5868](https://insights.sbomify.com/CVE-2025-5868/): RT-Thread lwp_syscall.c sys_thread_sigprocmask array index (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-5867 and fix it if it is affected.

What it is: CVE-2025-5867 is a high-severity vulnerability in RT-Thread, published on 9 Jun 2025. 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-2025-5867 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-2025-5867/ (Markdown: https://insights.sbomify.com/CVE-2025-5867/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-5867
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-5867
- OSV: https://osv.dev/vulnerability/CVE-2025-5867

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-5867/
Summaries are generated and may contain mistakes; the official description above is the record.