CVE-2024-27308: Mio Use-After-Free Vulnerability

CVE-2024-27308 Overview

CVE-2024-27308 is a use-after-free vulnerability affecting Mio, a Metal I/O library for Rust. When using named pipes on Windows, Mio can return invalid tokens that correspond to named pipes that have already been deregistered from the mio registry. This vulnerability is particularly concerning for applications using Tokio, where it can result in a use-after-free condition that may lead to memory corruption or code execution.

Critical Impact

This use-after-free vulnerability in Mio's Windows named pipe handling can lead to memory corruption. Applications storing pointers in tokens are especially at risk, and Tokio users face potential use-after-free conditions that could compromise system integrity.

Affected Products

• Mio versions v0.7.2 through v0.8.10 (Rust)
• Tokio versions v1.30.0 and later when using vulnerable Mio versions (Rust)
• Applications using Mio's named pipe functionality on Windows

Discovery Timeline

• 2024-03-06 - CVE CVE-2024-27308 published to NVD
• 2025-12-04 - Last updated in NVD database

Technical Details for CVE-2024-27308

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue that occurs when Mio returns invalid tokens for named pipes that have already been deregistered from the registry. The impact varies depending on how the application uses Mio. For applications that ignore or log invalid tokens, the consequence may be limited to warnings or application crashes. However, for applications that store pointers in tokens—which is common in asynchronous I/O patterns—this vulnerability can result in a use-after-free condition, potentially allowing an attacker to manipulate memory and achieve arbitrary code execution.

The vulnerability is network-accessible and requires no privileges or user interaction to exploit, making it particularly dangerous in exposed Windows services using named pipes for inter-process communication.

Root Cause

The root cause of this vulnerability lies in the improper handling of token lifecycle management within Mio's Windows named pipe implementation. When a named pipe is deregistered from the Mio registry, the corresponding token may still be returned to the application under certain race conditions or timing scenarios. This creates a situation where the application receives a token referencing a resource that no longer exists in the registry, leading to dangling pointer references when the application attempts to use the invalidated token.

Attack Vector

The attack vector for this vulnerability involves exploiting the timing window between named pipe deregistration and token return operations on Windows systems. An attacker could potentially trigger this condition by:

1. Establishing multiple named pipe connections to a vulnerable service
2. Manipulating the timing of connection establishment and teardown
3. Forcing the application to process tokens from deregistered pipes
4. Leveraging the resulting use-after-free to corrupt memory or gain code execution

This vulnerability is Windows-specific and only affects applications using named pipes. Other I/O resources handled by Mio are not affected by this issue.

The vulnerability mechanism involves token handling during the deregistration process. When a named pipe is removed from the Mio registry, the library may still return the associated token in subsequent poll operations. If the application has stored a pointer in this token and attempts to dereference it, it accesses freed memory. For detailed technical analysis, see the GitHub Security Advisory GHSA-r8w9-5wcg-vfj7.

Detection Methods for CVE-2024-27308

Indicators of Compromise

• Unexpected application crashes in Windows services using named pipes with Rust-based async I/O
• Memory access violations or segmentation faults in Tokio-based applications on Windows
• Anomalous behavior in applications following named pipe connection/disconnection cycles
• Debug logs indicating invalid or unexpected token values from Mio poll operations

Detection Strategies

• Audit application dependencies to identify vulnerable versions of Mio (v0.7.2 through v0.8.10) and Tokio (v1.30.0 and later)
• Implement runtime token validation to detect and log invalid tokens before processing
• Deploy memory sanitizers (AddressSanitizer) in development and testing environments to detect use-after-free conditions
• Monitor Windows Event Logs for application crashes related to memory access violations in Rust-based services

Monitoring Recommendations

• Configure crash dump collection for Windows services using named pipes to facilitate forensic analysis
• Implement application-level logging for named pipe registration and deregistration events
• Set up alerting for unexpected process terminations in Tokio-based services on Windows systems
• Use SentinelOne's behavioral detection capabilities to identify exploitation attempts targeting memory corruption vulnerabilities

How to Mitigate CVE-2024-27308

Immediate Actions Required

• Update Mio to version v0.8.11 or later immediately
• If using Tokio with Mio versions v0.7.2 through v0.8.10, verify Tokio is at a version prior to v1.30.0 or upgrade Mio
• Implement token validation as a workaround if immediate patching is not possible
• Review application code to ensure named pipe tokens are validated before use

Patch Information

The vulnerability has been fixed in Mio v0.8.11. The fix is available in commit 90d4fe00df870acd3d38f3dc4face9aacab8fbb9. Organizations should update their Cargo.toml to specify the patched version:

[dependencies]
mio = "0.8.11"

For additional details on the fix, refer to the GitHub Commit Update and GitHub Pull Request #1760.

Workarounds

• Implement token validation logic to detect and ignore invalid tokens returned by Mio before dereferencing any associated pointers
• Avoid storing raw pointers in Mio tokens; use indices or handles that can be safely validated
• Consider using Tokio versions prior to v1.30.0 if upgrading Mio is not immediately feasible (these versions ignore invalid tokens)
• Restrict named pipe access to trusted local processes where possible to reduce attack surface

# Update Mio dependency in Cargo project
cargo update -p mio
# Verify the installed version
cargo tree -p mio
# Rebuild the application with patched dependency
cargo build --release