CVE-2025-15411: Webassembly Wabt Use-After-Free Flaw

CVE-2025-15411 Overview

A memory corruption vulnerability has been identified in WebAssembly wabt versions up to 1.0.39. This vulnerability affects the function wabt::AST::InsertNode within the file /src/repro/wabt/bin/wasm-decompile of the wasm-decompile component. Successful exploitation allows an attacker to trigger memory corruption through manipulation of the affected function. The vulnerability requires local access to exploit and has been publicly disclosed with proof-of-concept code available.

Critical Impact
Memory corruption vulnerability in the wabt WebAssembly Binary Toolkit could lead to arbitrary code execution, denial of service, or information disclosure when processing malformed WebAssembly binaries. The project currently has no active maintainer, increasing risk for organizations relying on this tool.

Affected Products

WebAssembly wabt versions up to and including 1.0.39
wasm-decompile component
Systems using wabt for WebAssembly binary manipulation

Discovery Timeline

2026-01-01 - CVE-2025-15411 published to NVD
2026-01-06 - Last updated in NVD database

Technical Details for CVE-2025-15411

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists within the wabt::AST::InsertNode function in the wasm-decompile component of the WebAssembly Binary Toolkit. When processing specially crafted input, the function fails to properly validate memory boundaries, leading to memory corruption conditions.

The vulnerability requires local access to exploit, meaning an attacker would need the ability to provide malicious WebAssembly binary files to the wasm-decompile tool. While the attack complexity is low and no user interaction is required, the attacker does need low-level privileges on the target system.

A significant concern is that the wabt project currently lacks an active maintainer. When the vulnerability was reported through the GitHub issue tracker, the response indicated that researchers should provide their own patches via pull requests, suggesting an uncertain timeline for official remediation.

Root Cause

The root cause stems from improper bounds checking within the wabt::AST::InsertNode function. When the wasm-decompile component processes WebAssembly binary files, it parses and builds an Abstract Syntax Tree (AST) representation. During node insertion operations, the function does not adequately validate memory boundaries, allowing attackers to trigger out-of-bounds memory operations through specially crafted input files.

Attack Vector

The attack is conducted locally by providing a malicious WebAssembly binary file to the wasm-decompile tool. An attacker must have the ability to execute the wasm-decompile binary and supply it with a crafted input file. The exploitation mechanism involves manipulating the AST node insertion process to corrupt memory.

The vulnerability has been publicly documented with proof-of-concept materials available through GitHub PoC Code. The GitHub Issue Discussion provides additional technical context and vendor communication details.

Detection Methods for CVE-2025-15411

Indicators of Compromise

Unexpected crashes or segmentation faults when running wasm-decompile on WebAssembly binaries
Memory access violations or abnormal memory consumption patterns during wasm-decompile execution
Presence of unusually large or malformed .wasm files submitted for decompilation

Detection Strategies

Monitor for abnormal process behavior when wasm-decompile is executed, including unexpected termination or resource exhaustion
Implement file integrity monitoring on systems where wabt tools are installed to detect unauthorized modifications
Use memory sanitizers (AddressSanitizer, MemorySanitizer) in development environments to detect exploitation attempts

Monitoring Recommendations

Enable application crash logging and monitor for repeated wasm-decompile failures
Implement input validation for WebAssembly binaries before processing with wabt tools
Deploy endpoint detection capabilities to identify suspicious memory access patterns associated with wasm-decompile processes

How to Mitigate CVE-2025-15411

Immediate Actions Required

Restrict access to wasm-decompile and other wabt tools to trusted users only
Implement strict input validation for any WebAssembly binaries processed by wabt tools
Consider isolating wabt tool execution in sandboxed environments or containers
Monitor the GitHub issue for community-provided patches or official updates

Patch Information

As of the last update, no official patch has been released by the WebAssembly wabt project. The project currently lacks an active maintainer, and the response to the vulnerability disclosure suggested that researchers provide their own patches via pull requests. Organizations should monitor the official wabt repository for any community-contributed fixes.

Additional technical details and tracking information are available through VulDB #339332.

Workarounds

Run wasm-decompile in isolated environments such as containers or virtual machines to limit the impact of potential exploitation
Implement strict access controls to prevent untrusted users from executing wabt tools
Consider using alternative WebAssembly decompilation tools until an official patch is available
Apply memory safety mitigations at the OS level (ASLR, DEP/NX) to reduce exploitation success rates

bash

# Example: Running wasm-decompile in a restricted container
docker run --rm --read-only --security-opt=no-new-privileges \
  --cap-drop=ALL --network=none \
  -v /path/to/input:/input:ro \
  wabt-container wasm-decompile /input/module.wasm