# CVE-2026-3389: Squirrel sqstdrex.cpp sqstd_rex_newnode null pointer dereference

> A local attacker can cause a denial of service via null pointer dereference in the Squirrel scripting library's regex engine.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **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:** 1 Mar 2026
- **Updated:** 2 Mar 2026
- **Also known as:** DEBIAN-CVE-2026-3389, GHSA-g9mq-qjc2-8pgx, UBUNTU-CVE-2026-3389

## What is CVE-2026-3389?

CVE-2026-3389 is a medium-severity vulnerability in Squirrel, published on 1 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability was determined in Squirrel up to 3.2. This vulnerability affects the function sqstd_rex_newnode in the library sqstdlib/sqstdrex.cpp. Executing a manipulation can lead to null pointer dereference. The attack can only be executed locally. The exploit has been publicly disclosed and may be utilized. The project was informed of the problem early through an issue report but has not responded yet.

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

## Which versions are affected by CVE-2026-3389?

It affects 1 product.


Products: Squirrel-Lang Squirrel.

## How do I fix CVE-2026-3389?

No fix has been published for CVE-2026-3389 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3389 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3389 exists.

## Other vulnerabilities in Squirrel

- [CVE-2026-9541](https://insights.sbomify.com/CVE-2026-9541/): Squirrel Cnut File sqobject.cpp ReadObject heap-based overflow (medium 4.8)
- [CVE-2026-3388](https://insights.sbomify.com/CVE-2026-3388/): Squirrel sqcompiler.cpp UnaryOP recursion (medium 4.8)
- [CVE-2026-2659](https://insights.sbomify.com/CVE-2026-2659/): Squirrel sqfuncstate.cpp PopTarget out-of-bounds (medium 4.8)
- [CVE-2026-2661](https://insights.sbomify.com/CVE-2026-2661/): Squirrel sqobject.h operator heap-based overflow (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3389 and fix it if it is affected.

What it is: CVE-2026-3389 is a medium-severity vulnerability in Squirrel, published on 1 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-2026-3389 exists.

Affected product: Squirrel. 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-2026-3389/ (Markdown: https://insights.sbomify.com/CVE-2026-3389/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3389
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3389
- OSV: https://osv.dev/vulnerability/CVE-2026-3389

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3389/
Summaries are generated and may contain mistakes; the official description above is the record.