CVE-2026-44209

Deferred Deferred - Pending Action

Server-Side Template Injection in Banks Prompt Template Engine

Publication date: 2026-05-26

Last updated on: 2026-06-30

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-05-26

Last Modified

2026-06-30

Generated

2026-07-06

AI Q&A

2026-05-27

EPSS Evaluated

2026-07-04

NVD

CVE-2026-44209

Affected Vendors & Products

Vendor	Product	Version / Range
banks	jinja2	2.4.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-917	The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.
CWE-1336	The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.

Attack-Flow Graph

Executive Summary

This vulnerability occurs in the Banks software prior to version 2.4.2, where it uses an unsandboxed jinja2.Environment() to render prompt templates. If an application passes user-supplied strings as the template argument to the Prompt() function, it becomes vulnerable to Server-Side Template Injection (SSTI). This means an attacker can inject malicious template code that the server executes, potentially leading to Remote Code Execution (RCE) on the host system.

Impact Analysis

The vulnerability can allow an attacker to execute arbitrary code remotely on the affected server. This can lead to unauthorized access, data theft, data manipulation, service disruption, or complete takeover of the host system running the vulnerable software.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade the Banks software to version 2.4.2 or later, where the issue has been fixed.

Avoid passing user-supplied strings directly as the template argument to Prompt() when using jinja2.Environment() to prevent Server-Side Template Injection (SSTI).

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