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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-61536: 0.38% estimated exploitation activity in the next 30 days; percentile 32.01 (FIRST EPSS, 2026-11-10). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary `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…

Published by the source

5 Nov 2026, 17:51 UTC

Last modified by the source

5 Nov 2026, 18:00 UTC

Source last checked

6 Nov 2026, 06:05 UTC

1. Revision 2 · amended · 6 Nov 2026

   Amended from osv record GHSA-64vx-6h2c-rjh7

2. Revision 1 · created · 5 Nov 2026

   Published from ghsa record GHSA-64vx-6h2c-rjh7

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-61536

Advisory: Banks: Unsafe importlib.import_module of attacker-controlled Tool.import_path in CompletionExtension allows RCE
IDs: CVE-2026-61536, GHSA-64vx-6h2c-rjh7
Record: https://patchnext.com/advisories/cve-2026-61536 (revision 2, source checked 6 Nov 2026, 06:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: banks 2.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI banks: affected < 2.4.3; fixed in 2.4.3

## Suggested inspection (read-only)
- `python -m pip show banks`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on banks.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-64vx-6h2c-rjh7 (GitHub-reviewed advisory GHSA-64vx-6h2c-rjh7 lists affected ranges: PyPI banks >=0 <=2.4.2)
- Verified: https://osv.dev/vulnerability/GHSA-64vx-6h2c-rjh7 (OSV record GHSA-64vx-6h2c-rjh7 lists affected ranges: PyPI banks >=0 <2.4.3 (fixed))

Commands are suggestions: review each one before running it.