# CVE-2026-40342: Firebird: Path Traversal + Arbitrary File Write Leads to Remote Code Execution

> An authenticated user with CREATE FUNCTION privileges can achieve remote code execution via path traversal in the external engine plugin loader.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Apr 2026
- **Updated:** 22 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-40342, ECHO-6873-b8db-a927, GHSA-7pxc-h3rv-r257, UBUNTU-CVE-2026-40342

## What is CVE-2026-40342?

CVE-2026-40342 is a critical path traversal vulnerability in FirebirdSQL firebird, published on 17 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the external engine plugin loader concatenates a user-supplied engine name into a filesystem path without filtering path separators or .. components. An authenticated user with CREATE FUNCTION privileges can use a crafted ENGINE name to load an arbitrary shared library from anywhere on the filesystem via path traversal. The library's initialization code executes immediately during loading, before Firebird validates the module, achieving code execution as the server's OS account. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-427 (Uncontrolled Search Path Element), CWE-73 (External Control of File Name or Path), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-40342?

It affects 1 product.


Products: Firebirdsql Firebird.

## How do I fix CVE-2026-40342?

Upgrade to a fixed version.

## Is CVE-2026-40342 being exploited?

There is no known exploitation of CVE-2026-40342 in the wild and no public exploit code.

## Other vulnerabilities in FirebirdSQL firebird

- [CVE-2008-0467](https://insights.sbomify.com/CVE-2008-0467/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-4992](https://insights.sbomify.com/CVE-2007-4992/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-5245](https://insights.sbomify.com/CVE-2007-5245/): Memory corruption in n/a (critical 10.0)
- [CVE-2007-5246](https://insights.sbomify.com/CVE-2007-5246/): Memory corruption in n/a (critical 10.0)
- [CVE-2017-6369](https://insights.sbomify.com/CVE-2017-6369/): Code injection in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40342 and fix it if it is affected.

What it is: CVE-2026-40342 is a critical path traversal vulnerability in FirebirdSQL firebird, published on 17 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40342 in the wild and no public exploit code.

Affected product: FirebirdSQL firebird. 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-2026-40342/ (Markdown: https://insights.sbomify.com/CVE-2026-40342/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40342
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40342
- OSV: https://osv.dev/vulnerability/CVE-2026-40342

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40342/
Summaries are generated and may contain mistakes; the official description above is the record.