# CVE-2026-61536: Banks: Unsafe importlib.import_module of attacker-controlled Tool.import_path in CompletionExtension allows RCE

> Attackers can achieve remote code execution in the hosting process by supplying malicious tool import paths that bypass sandboxing via unsafe dynamic module loading.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/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:** No
- **Published:** 30 Jul 2026
- **Updated:** 31 Jul 2026
- **Also known as:** GHSA-64vx-6h2c-rjh7

## What is CVE-2026-61536?

CVE-2026-61536 is a high-severity code injection vulnerability in masci banks, published on 30 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Banks generates meaningful LLM prompts using a simple template language. In versions prior to 2.4.3, banks parses Tool JSON objects from the rendered body of {% completion %} blocks and later resolves their import_path field through importlib.import_module(...) + getattr(...) to obtain the callable that handles a tool call. There is no allowlist or sanitization on import_path, so any importable Python attribute (e.g. os.system, subprocess.getoutput) can be selected. When the LLM emits a tool_calls entry whose function.name matches the attacker-supplied tool name, the resolved callable is invoked with kwargs decoded from tool_call.function.arguments, yielding arbitrary code execution in the banks-hosting process. This is distinct from GHSA-gphh-9q3h-jgpp / CVE-2026-44209. That advisory was fixed in 2.4.2 by switching src/banks/env.py from Environment to SandboxedEnvironment. The fix does not touch src/banks/extensions/completion.py, and the unsafe import + getattr chain still executes on 2.4.2. The malicious Tool JSON is plain text in the rendered template body — it requires no Jinja attribute access, so the sandbox is irrelevant. This issue has been fixed in version 2.4.3.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-470 (Use of Externally-Controlled Input to Select Classes or Code)

## Which versions are affected by CVE-2026-61536?


## How do I fix CVE-2026-61536?

No fix has been published for CVE-2026-61536 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-61536 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61536 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61536 and fix it if it is affected.

What it is: CVE-2026-61536 is a high-severity code injection vulnerability in masci banks, published on 30 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61536 exists.

Affected product: masci banks. 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-2026-61536/ (Markdown: https://insights.sbomify.com/CVE-2026-61536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61536
- OSV: https://osv.dev/vulnerability/CVE-2026-61536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61536/
Summaries are generated and may contain mistakes; the official description above is the record.