CVE-2025-66434: erpnext Code Injection — Exploit

Description

An SSTI (Server-Side Template Injection) vulnerability exists in the get_dunning_letter_text method of Frappe ERPNext through 15.89.0. The function renders attacker-controlled Jinja2 templates (body_text) using frappe.render_template() with a user-supplied context (doc). Although Frappe uses a custom SandboxedEnvironment, several dangerous globals such as frappe.db.sql are still available in the execution context via get_safe_globals(). An authenticated attacker with access to configure Dunning Type and its child table Dunning Letter Text can inject arbitrary Jinja expressions, resulting in server-side code execution within a restricted but still unsafe context. This can leak database information.

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CVSS v3.1 Score

8.8

HIGH

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

Weakness Type (CWE)

CWE-94 CWE-94

CWE-1336 CWE-1336

Affected Products

Vendor	Product	Versions
frappe	erpnext	< 15.89.0

References

Exploits

https://iamanc.github.io/post/erpnext-ssti-bug-1 https://www.notion.so/SSTI-bug-1-239e6086eadc8096bfcfe90551a3a483?source=copy_link

Frequently Asked Questions

What is CVE-2025-66434? +

An SSTI (Server-Side Template Injection) vulnerability exists in the get_dunning_letter_text method of Frappe ERPNext through 15.89.0. The function renders attacker-controlled Jinja2 templates (body_text) using frappe.render_template() with a user-supplied context (doc). Although Frappe uses a custom SandboxedEnvironment, several dangerous globals such as frappe.db.sql are still available in the execution context via get_safe_globals(). An authenticated attacker with access to configure Dunning Type and its child table Dunning Letter Text can inject arbitrary Jinja expressions, resulting in server-side code execution within a restricted but still unsafe context. This can leak database information. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-66434? +

CVE-2025-66434 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-66434? +

CVE-2025-66434 affects products from frappe, specifically: erpnext. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-66434? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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