Frappe ERPNext up to 15.89.0 Jinja2 Template render_template special elements used in a template engine

Summaryinfo

A vulnerability was found in Frappe ERPNext up to 15.89.0. It has been rated as critical. This issue affects the function render_template of the component Jinja2 Template Handler. Performing a manipulation results in improper neutralization of special elements used in a template engine. This vulnerability was named CVE-2025-66434. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability classified as critical has been found in Frappe ERPNext up to 15.89.0. This affects the function render_template of the component Jinja2 Template Handler. The manipulation with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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 is possible to read the advisory at notion.so. This vulnerability is uniquely identified as CVE-2025-66434 since 11/30/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/24/2025). The attack technique deployed by this issue is T1221 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-203397). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• Frappe

Name

• ERPNext

Version

• 15.0
• 15.1
• 15.2
• 15.3
• 15.4
• 15.5
• 15.6
• 15.7
• 15.8
• 15.9
• 15.10
• 15.11
• 15.12
• 15.13
• 15.14
• 15.15
• 15.16
• 15.17
• 15.18
• 15.19
• 15.20
• 15.21
• 15.22
• 15.23
• 15.24
• 15.25
• 15.26
• 15.27
• 15.28
• 15.29
• 15.30
• 15.31
• 15.32
• 15.33
• 15.34
• 15.35
• 15.36
• 15.37
• 15.38
• 15.39
• 15.40
• 15.41
• 15.42
• 15.43
• 15.44
• 15.45
• 15.46
• 15.47
• 15.48
• 15.49
• 15.50
• 15.51
• 15.52
• 15.53
• 15.54
• 15.55
• 15.56
• 15.57
• 15.58
• 15.59
• 15.60
• 15.61
• 15.62
• 15.63
• 15.64
• 15.65
• 15.66
• 15.67
• 15.68
• 15.69
• 15.70
• 15.71
• 15.72
• 15.73
• 15.74
• 15.75
• 15.76
• 15.77
• 15.78
• 15.79
• 15.80
• 15.81
• 15.82
• 15.83
• 15.84
• 15.85
• 15.86
• 15.87
• 15.88
• 15.89.0

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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