Scriban before 7.0.0 (affected versions <= 6.6.0) contains an uncontrolled memory allocation vulnerability in the string.pad_left and string.pad_right template functions, which perform no validation on the width parameter before delegating to .NET's String.PadLeft/PadRight. When an application exposes Scriban to untrusted template input, an attacker can supply an arbitrarily large width value (e.g., 500,000,000) to trigger ~1GB memory allocations in a single call, resulting in OutOfMemoryException and denial of service. The TemplateContext.LimitToString limit does not prevent this because it is only enforced after the string has been fully allocated.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v4.0