# CVE-2025-7207: mruby nregs codegen.c scope_new heap-based overflow

> A heap-based buffer overflow in mruby's compiler allows local attackers to execute arbitrary code or cause denial of service.

- **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:** Yes
- **Published:** 9 Jul 2025
- **Updated:** 9 Jul 2025
- **Also known as:** DEBIAN-CVE-2025-7207, GHSA-48pr-6hvf-39v3, UBUNTU-CVE-2025-7207

## What is CVE-2025-7207?

CVE-2025-7207 is a medium-severity memory corruption vulnerability in mruby, published on 9 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability, which was classified as problematic, was found in mruby up to 3.4.0-rc2. Affected is the function scope_new of the file mrbgems/mruby-compiler/core/codegen.c of the component nregs Handler. The manipulation leads to heap-based buffer overflow. An attack has to be approached locally. The exploit has been disclosed to the public and may be used. The name of the patch is 1fdd96104180cc0fb5d3cb086b05ab6458911bb9. It is recommended to apply a patch to fix this issue.

Weakness: CWE-122 (Heap-based Buffer Overflow), CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2025-7207?

It affects 1 product.


Products: Mruby Mruby.

## How do I fix CVE-2025-7207?

Apply the vendor's patch.

## Is CVE-2025-7207 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-7207 exists.

## Other vulnerabilities in mruby

- [CVE-2020-6838](https://insights.sbomify.com/CVE-2020-6838/): Use after free in n/a (critical 9.8)
- [CVE-2020-6839](https://insights.sbomify.com/CVE-2020-6839/): Memory corruption in n/a (critical 9.8)
- [CVE-2020-6840](https://insights.sbomify.com/CVE-2020-6840/): Use after free in n/a (critical 9.8)
- [CVE-2018-10199](https://insights.sbomify.com/CVE-2018-10199/): Use after free in n/a (critical 9.8)
- [CVE-2022-1212](https://insights.sbomify.com/CVE-2022-1212/): Use-After-Free in str_escape in mruby/mruby in mruby/mruby (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-7207 and fix it if it is affected.

What it is: CVE-2025-7207 is a medium-severity memory corruption vulnerability in mruby, published on 9 Jul 2025. 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-2025-7207 exists.

Affected product: mruby. 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-2025-7207/ (Markdown: https://insights.sbomify.com/CVE-2025-7207/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-7207
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-7207
- OSV: https://osv.dev/vulnerability/CVE-2025-7207

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-7207/
Summaries are generated and may contain mistakes; the official description above is the record.