CVE-2025-15413: wasm3 Buffer Overflow Vulnerability

CVE-2025-15413 Overview

A memory corruption vulnerability has been discovered in wasm3, a high-performance WebAssembly interpreter written in C. The vulnerability affects the op_SetSlot_i32 and op_CallIndirect functions within the m3_exec.h file. Local attackers can exploit this flaw through manipulation of WebAssembly bytecode, potentially leading to memory corruption conditions. The exploit has been publicly disclosed, and notably, the wasm3 project currently lacks active maintainers, which significantly complicates remediation efforts.

Critical Impact

Memory corruption in the wasm3 interpreter can lead to arbitrary memory manipulation, potentially enabling code execution or denial of service in applications using wasm3 for WebAssembly execution.

Affected Products

• wasm3 versions up to and including 0.5.0
• Applications and embedded systems utilizing wasm3 as a WebAssembly runtime
• IoT devices and edge computing platforms running wasm3-based interpreters

Discovery Timeline

• January 1, 2026 - CVE-2025-15413 published to NVD
• January 2, 2026 - Last updated in NVD database

Technical Details for CVE-2025-15413

Vulnerability Analysis

This vulnerability falls under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The affected functions op_SetSlot_i32 and op_CallIndirect in m3_exec.h fail to properly validate memory boundaries during slot operations and indirect function calls in the WebAssembly execution environment.

The wasm3 interpreter processes WebAssembly bytecode and executes operations through a series of opcode handlers. When processing slot assignment operations or indirect call instructions, insufficient bounds checking allows an attacker to corrupt adjacent memory regions. This can destabilize the interpreter's internal state and potentially affect the host application's memory space.

The local attack vector requires the attacker to supply maliciously crafted WebAssembly modules to a target system running wasm3. Since WebAssembly is commonly used for sandboxed execution of untrusted code, this vulnerability undermines the security guarantees that wasm3 is expected to provide.

Root Cause

The root cause lies in improper bounds validation within the memory slot manipulation routines. The op_SetSlot_i32 function writes 32-bit integer values to stack slots without adequate verification that the target slot index falls within allocated bounds. Similarly, op_CallIndirect performs indirect function table lookups that can reference out-of-bounds memory when processing malformed call instructions.

The memory corruption occurs because the interpreter trusts WebAssembly bytecode values that specify memory offsets and indices without sufficient sanitization, allowing controlled writes to unintended memory locations.

Attack Vector

The vulnerability requires local access and the ability to provide WebAssembly modules to the wasm3 interpreter. An attacker would craft a malicious .wasm file containing specially constructed bytecode that triggers the vulnerable code paths in m3_exec.h.

Attack scenarios include:

• Uploading malicious WebAssembly modules to web applications using wasm3 server-side
• Exploiting IoT devices that accept WebAssembly-based plugins or extensions
• Targeting edge computing platforms where wasm3 is used for workload isolation

The vulnerability mechanism involves crafting WebAssembly bytecode that manipulates slot indices or indirect call table references to trigger out-of-bounds memory operations. For detailed technical analysis, refer to GitHub Issue #543 and GitHub Issue #547.

Detection Methods for CVE-2025-15413

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications using wasm3
• Memory access violations logged by operating system memory protection mechanisms
• Abnormal WebAssembly module uploads or processing attempts
• Stack corruption indicators in crash dumps associated with m3_exec.h functions

Detection Strategies

• Deploy application-level monitoring to detect wasm3 interpreter crashes or abnormal terminations
• Implement WebAssembly module validation before processing to detect malformed bytecode
• Use memory sanitizers (ASan, MSan) in development environments to catch out-of-bounds access
• Monitor system logs for memory corruption signatures associated with wasm3 processes

Monitoring Recommendations

• Enable core dump analysis for systems running wasm3-based applications
• Implement rate limiting and anomaly detection for WebAssembly module submissions
• Deploy SentinelOne Singularity Platform for runtime memory protection and behavioral analysis
• Audit wasm3 integration points to identify exposed attack surfaces

How to Mitigate CVE-2025-15413

Immediate Actions Required

• Audit all systems and applications using wasm3 to identify vulnerable deployments
• Implement strict input validation for WebAssembly modules before processing
• Consider migrating to actively maintained WebAssembly runtimes such as wasmtime or wasmer
• Restrict access to systems accepting WebAssembly module uploads to trusted sources only

Patch Information

No official patch is currently available as the wasm3 project lacks active maintenance. Organizations should evaluate alternative WebAssembly runtimes with active security support. Community-developed fixes may be tracked via GitHub Issue #543 and GitHub Issue #547. Additional vulnerability details are available at VulDB #339334.

Workarounds

• Disable WebAssembly module processing in production systems until migration to a maintained runtime
• Implement network segmentation to isolate systems running wasm3 from untrusted inputs
• Deploy application sandboxing (containers, seccomp filters) to limit impact of potential exploitation
• Enable OS-level memory protections (ASLR, DEP/NX) to increase exploitation difficulty

# Example: Restrict wasm3 process with seccomp and reduced capabilities
# Note: This limits but does not eliminate the vulnerability risk

# Run wasm3-based application with reduced privileges
sudo setcap -r /path/to/wasm3_application

# Apply seccomp profile to restrict system calls
# (requires application-specific seccomp profile configuration)
docker run --security-opt seccomp=/path/to/wasm3-seccomp.json your-wasm3-container