mruby Heap-Based Buffer Overflow Vulnerability in Code Generation Component

A heap-based buffer overflow vulnerability has been identified in mruby versions through 3.4.0-rc2. The issue arises in the 'scope_new' function within the 'mrbgems/mruby-compiler/core/codegen.c' file, specifically related to the nregs handler. This vulnerability requires local access to exploit and has been publicly disclosed, with an available proof-of-concept exploit.

Impact

Exploitation of this vulnerability leads to a heap-based buffer overflow, which can commonly result in arbitrary code execution or causing a program to crash.

Reproduction

The vulnerability can be reproduced using a fuzzing harness available in the 'oss-fuzz' repository. After compiling mruby with AddressSanitizer enabled, the fuzzer can be run with a crafted input that triggers the buffer overflow.

Remediation

Users are advised to update to the latest version of mruby, where this vulnerability has been patched.