fix: remove unsafe exec() in 0x0012-writefile.c

[orbisai0security]

Summary

Fix critical severity security issue in 0x0012-writefile/0x0012-writefile.c.

Vulnerability

Field	Value
ID	V-002
Severity	CRITICAL
Scanner	multi_agent_ai
Rule	V-002
File	0x0012-writefile/0x0012-writefile.c:1

Description: The writefile (and potentially copyfile) module uses sprintf() to format strings into fixed-size stack buffers without specifying a maximum output length. sprintf() has no built-in bounds checking — it writes as many bytes as the formatted output requires, regardless of the destination buffer's capacity. An attacker who can control the input data (such as a filename or file path) can supply a string long enough to overflow the buffer, overwrite adjacent stack memory including the saved return address, and redirect program execution to attacker-controlled code.

Changes

• 0x0012-writefile/0x0012-writefile.c

Verification

• Build passes
• Scanner re-scan confirms fix
• LLM code review passed

---

Automated security fix by OrbisAI Security