# CVE-2019-25569: RealTerm Serial Terminal 2.0.0.70 SEH Overflow Crash

> Local attackers can crash RealTerm Serial Terminal by triggering a stack-based buffer overflow via crafted input in the Echo Port field.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/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:** 21 Mar 2026
- **Updated:** 23 Mar 2026
- **Also known as:** GHSA-qm4h-vmrq-638h

## What is CVE-2019-25569?

CVE-2019-25569 is a medium-severity memory corruption vulnerability in RealTerm: Serial Terminal, published on 21 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

RealTerm Serial Terminal 2.0.0.70 contains a stack-based buffer overflow vulnerability in the Echo Port field that allows local attackers to crash the application by triggering a structured exception handler (SEH) chain corruption. Attackers can craft a malicious input string with 268 bytes of padding followed by SEH overwrite values and paste it into the Port field to cause denial of service.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2019-25569?

It affects 1 product.


Products: Crun Realterm.

## How do I fix CVE-2019-25569?

No fix has been published for CVE-2019-25569 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-25569 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-25569 exists.

## Other vulnerabilities in RealTerm: Serial Terminal

- [CVE-2019-25679](https://insights.sbomify.com/CVE-2019-25679/): RealTerm Serial Terminal 2.0.0.70 Buffer Overflow SEH (high 8.5)
- [CVE-2019-25570](https://insights.sbomify.com/CVE-2019-25570/): RealTerm Serial Terminal 2.0.0.70 Denial of Service via Port Field (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-25569 and fix it if it is affected.

What it is: CVE-2019-25569 is a medium-severity memory corruption vulnerability in RealTerm: Serial Terminal, published on 21 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-25569 exists.

Affected product: RealTerm: Serial Terminal. 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-2019-25569/ (Markdown: https://insights.sbomify.com/CVE-2019-25569/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-25569
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-25569
- OSV: https://osv.dev/vulnerability/CVE-2019-25569

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-25569/
Summaries are generated and may contain mistakes; the official description above is the record.