# CVE-2019-25627: FlexHEX 2.71 Local Buffer Overflow via SEH Unicode

> Local attackers can execute arbitrary code by triggering a buffer overflow in the Stream Name field of FlexHEX via a crafted file.

- **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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:** 24 Mar 2026
- **Updated:** 1 Oct 2026
- **Also known as:** GHSA-4g2g-3x54-996g

## What is CVE-2019-25627?

CVE-2019-25627 is a high-severity memory corruption vulnerability in FlexHEX, published on 24 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

FlexHEX 2.71 contains a local buffer overflow vulnerability in the Stream Name field that allows local attackers to execute arbitrary code by triggering a structured exception handler (SEH) overflow. Attackers can craft a malicious text file with carefully aligned shellcode and SEH chain pointers, paste the contents into the Stream Name dialog, and execute arbitrary commands like calc.exe when the exception handler is triggered.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2019-25627?

It affects 1 product.


Products: Flexhex Flexhex.

## How do I fix CVE-2019-25627?

No fix has been published for CVE-2019-25627 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-25627 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-25627 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-25627 and fix it if it is affected.

What it is: CVE-2019-25627 is a high-severity memory corruption vulnerability in FlexHEX, published on 24 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-2019-25627 exists.

Affected product: FlexHEX. 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-2019-25627/ (Markdown: https://insights.sbomify.com/CVE-2019-25627/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-25627
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-25627
- OSV: https://osv.dev/vulnerability/CVE-2019-25627

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-25627/
Summaries are generated and may contain mistakes; the official description above is the record.