CVE-2024-22667: Vim Buffer Overflow Vulnerability

CVE-2024-22667 Overview

CVE-2024-22667 is a stack-based buffer overflow vulnerability affecting Vim text editor versions prior to 9.0.2142. The vulnerability exists in the did_set_langmap function within map.c, where an unsafe sprintf call writes to an error buffer that is passed down to option callback functions. This memory corruption issue can potentially be exploited by an attacker to execute arbitrary code on a victim's system when a user opens a maliciously crafted file or executes certain Vim commands.

Critical Impact

This stack-based buffer overflow in Vim can lead to arbitrary code execution with the privileges of the user running the editor, potentially compromising system integrity and confidentiality.

Affected Products

• Vim versions prior to 9.0.2142
• Fedora 38
• Fedora 39

Discovery Timeline

• February 5, 2024 - CVE-2024-22667 published to NVD
• November 4, 2025 - Last updated in NVD database

Technical Details for CVE-2024-22667

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), specifically a stack-based buffer overflow. The flaw resides in Vim's language mapping functionality, where the did_set_langmap function in map.c improperly handles error message formatting. When processing certain langmap options, the function uses sprintf to write formatted error messages to a buffer without adequate bounds checking. Since this buffer is allocated on the stack and passed through option callback functions, an attacker can craft input that causes the buffer to overflow, corrupting adjacent stack memory.

The local attack vector requires user interaction—typically opening a malicious file or executing a crafted Vim command. However, if successfully exploited, the vulnerability enables an attacker to achieve full compromise of confidentiality, integrity, and availability of the affected system at the privilege level of the Vim process.

Root Cause

The root cause stems from the use of the unsafe sprintf function for writing error messages without proper length validation. The did_set_langmap function passes an error buffer through the option callback chain, and when error conditions arise, sprintf writes to this buffer without checking if the output exceeds the allocated stack space. This classic C programming mistake allows specially crafted input to overflow the buffer boundaries.

Attack Vector

The attack requires local access with user interaction. An attacker must convince a user to open a maliciously crafted file in Vim or execute specific commands that trigger the vulnerable langmap option processing. The exploitation involves:

1. Crafting input that triggers the did_set_langmap function with parameters designed to generate an oversized error message
2. The sprintf call writes beyond the stack buffer boundaries
3. Stack memory corruption enables potential control flow hijacking
4. Arbitrary code execution occurs with the privileges of the Vim process

Since no public exploit code is currently available and this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog, active exploitation has not been confirmed in the wild.

Detection Methods for CVE-2024-22667

Indicators of Compromise

• Unexpected Vim crashes or segmentation faults when processing files with unusual langmap configurations
• Core dumps showing stack corruption originating from the did_set_langmap function in map.c
• Suspicious Vim configuration files or modelines containing abnormally long langmap option values

Detection Strategies

• Monitor for Vim process crashes associated with memory corruption, particularly involving the langmap functionality
• Implement file integrity monitoring for Vim configuration files (~/.vimrc, /etc/vim/vimrc) to detect malicious modifications
• Deploy endpoint detection solutions capable of identifying stack-based buffer overflow exploitation attempts
• Enable crash dump analysis to identify exploitation attempts targeting this vulnerability

Monitoring Recommendations

• Configure system logging to capture Vim process crashes and abnormal terminations
• Implement application allowlisting and monitoring for unexpected child processes spawned by Vim
• Monitor for attempts to modify Vim configuration files with unusually long langmap option values
• SentinelOne Singularity platform provides behavioral analysis that can detect exploitation attempts and post-exploitation activity

How to Mitigate CVE-2024-22667

Immediate Actions Required

• Upgrade Vim to version 9.0.2142 or later immediately on all affected systems
• Review and validate Vim configuration files for suspicious langmap configurations
• Apply operating system vendor patches as they become available for your distribution
• Consider restricting Vim's ability to process untrusted files until patching is complete

Patch Information

The Vim development team has addressed this vulnerability in commit b39b240c386a5a29241415541f1c99e2e6b8ce47. The fix properly bounds-checks the error buffer writes in the did_set_langmap function. Users should upgrade to Vim version 9.0.2142 or later. Distribution-specific patches are available through:

• Vim GitHub Commit - Official fix
• Fedora Package Announcement - Fedora 38/39 updates
• Debian LTS Announcement - Debian security update
• NetApp Security Advisory - NetApp product guidance

Workarounds

• Avoid opening untrusted files in Vim until the system is patched
• Disable langmap functionality by adding set nolangremap to your Vim configuration if not required
• Use alternative text editors for processing files from untrusted sources
• Implement strict file permission controls to prevent unauthorized modification of Vim configuration files

# Update Vim on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade vim

# Update Vim on Fedora systems
sudo dnf update vim

# Verify Vim version after update (should be 9.0.2142 or later)
vim --version | head -n 1