CVE-2018-25305: librsvg2-bin Buffer Overflow Vulnerability

CVE-2018-25305 Overview

CVE-2018-25305 is a buffer overflow vulnerability affecting librsvg2-bin version 2.40.13, a library used to render SVG files. This vulnerability allows local attackers to cause a denial of service condition by processing specially crafted, malformed SVG files. When exploited, attackers can supply malicious SVG input to the rsvg conversion tool, triggering a segmentation fault in the cairo image compositor component.

Critical Impact

Local attackers can crash applications using librsvg2-bin by supplying malformed SVG files, causing denial of service through segmentation faults in the cairo image compositor.

Affected Products

• librsvg2-bin version 2.40.13

Discovery Timeline

• 2026-04-29 - CVE-2018-25305 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2018-25305

Vulnerability Analysis

This buffer overflow vulnerability (CWE-120) exists in librsvg2-bin version 2.40.13, specifically affecting the SVG processing pipeline. The vulnerability occurs when the library processes malformed SVG input, leading to memory corruption in the cairo image compositor. The attack requires local access but does not require any privileges or user interaction, making it relatively straightforward to exploit on systems where users can supply SVG files for processing.

The vulnerability results in high availability impact, as successful exploitation causes a segmentation fault that crashes the processing application. While there is no direct impact to confidentiality or integrity, the denial of service condition can disrupt critical image processing workflows.

Root Cause

The root cause of this vulnerability is improper bounds checking (CWE-120: Buffer Copy without Checking Size of Input) in the SVG parsing and rendering pipeline. When librsvg2-bin processes a specially crafted SVG file, it fails to properly validate input dimensions or data lengths before copying data into fixed-size buffers. This allows an attacker to provide input that exceeds the buffer's allocated memory space, corrupting adjacent memory regions and ultimately causing a segmentation fault in the cairo image compositor.

Attack Vector

The attack vector is local, requiring an attacker to have the ability to supply SVG files to a system running the vulnerable librsvg2-bin component. Exploitation involves crafting a malformed SVG file with specific characteristics designed to trigger the buffer overflow condition. When the vulnerable rsvg conversion tool processes this file, the malformed input causes memory corruption that results in a segmentation fault.

Attack scenarios include:

• Web applications that accept user-uploaded SVG files for conversion or rendering
• Desktop applications that process SVG files from untrusted sources
• Automated image processing pipelines that handle SVG content
• Command-line usage of the rsvg-convert utility with untrusted input

For technical details on exploitation, refer to the Exploit-DB advisory #44491 which documents the vulnerability mechanism.

Detection Methods for CVE-2018-25305

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications using librsvg2-bin
• Core dump files generated by rsvg-convert or related processes
• Abnormal SVG files with unusual structure or excessive nested elements in upload directories
• Error logs indicating memory corruption or invalid memory access in cairo components

Detection Strategies

• Monitor system logs for segmentation faults associated with rsvg-convert or applications using librsvg2
• Implement file integrity monitoring for SVG upload directories to detect suspicious file patterns
• Deploy application crash monitoring to alert on repeated failures in SVG processing components
• Use SentinelOne's behavioral detection to identify anomalous process crashes and memory access patterns

Monitoring Recommendations

• Configure centralized logging to capture application crashes and core dumps from SVG processing services
• Implement rate limiting on SVG file uploads to mitigate potential denial of service amplification
• Monitor process stability metrics for services that depend on librsvg2-bin
• Enable auditd or similar system auditing to track rsvg-convert invocations with untrusted input

How to Mitigate CVE-2018-25305

Immediate Actions Required

• Identify all systems running librsvg2-bin version 2.40.13 through package inventory
• Upgrade librsvg2-bin to a patched version that addresses the buffer overflow
• Implement input validation for SVG files before processing with librsvg2
• Restrict access to SVG processing functionality to trusted users where possible

Patch Information

Organizations should update librsvg2-bin to a version newer than 2.40.13 that includes fixes for this buffer overflow vulnerability. Consult your Linux distribution's package repository for the appropriate patched version. Additional technical details are available in the Vulncheck Advisory for librsvg2 Buffer Overflow.

Workarounds

• Implement SVG sanitization using alternative libraries before processing with librsvg2-bin
• Run SVG processing in isolated containers or sandboxed environments to limit denial of service impact
• Disable or restrict SVG processing capabilities until patching is complete
• Use resource limits (ulimit) to contain the impact of potential crashes on system stability

# Configuration example
# Run rsvg-convert in a sandboxed environment with resource limits
# This limits potential denial of service impact

# Set process limits before invoking rsvg-convert
ulimit -v 512000  # Limit virtual memory to 512MB
ulimit -t 30      # Limit CPU time to 30 seconds

# Alternative: Use firejail for sandboxing
firejail --private --net=none rsvg-convert input.svg -o output.png