CVE-2025-27598
📋 TL;DR
An out-of-bounds write vulnerability in ImageSharp's GIF decoder allows attackers to cause denial of service by crashing applications processing specially crafted GIF files. This affects all applications using vulnerable versions of ImageSharp for GIF image processing. The vulnerability has been patched in recent releases.
💻 Affected Systems
- SixLabors.ImageSharp
📦 What is this software?
Imagesharp by Sixlabors
Imagesharp by Sixlabors
⚠️ Risk & Real-World Impact
Worst Case
Complete application crash leading to denial of service, potentially disrupting critical image processing workflows or web services.
Likely Case
Application instability or crashes when processing malicious GIF files, resulting in temporary service disruption.
If Mitigated
No impact if patched versions are used or if GIF processing is disabled.
🎯 Exploit Status
Attack requires only a specially crafted GIF file to be processed by vulnerable code. No authentication or special privileges needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.1.7 or 2.1.10
Vendor Advisory: https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-2cmq-823j-5qj8
Restart Required: No
Instructions:
1. Update ImageSharp package via NuGet: 'dotnet add package SixLabors.ImageSharp --version 3.1.7' (or 2.1.10 for v2). 2. Rebuild and redeploy your application. 3. Test GIF processing functionality.
🔧 Temporary Workarounds
Disable GIF processing
allTemporarily disable GIF image processing in your application until patching is complete.
Implement file type validation to reject GIF files
Configure image processing pipeline to skip GIF format
🧯 If You Can't Patch
- Implement strict file validation to reject suspicious or malformed GIF files
- Deploy web application firewall (WAF) rules to block malicious GIF uploads
🔍 How to Verify
Check if Vulnerable:
Check your project's package references for SixLabors.ImageSharp version. If version is below 3.1.7 (for v3) or 2.1.10 (for v2), you are vulnerable.Check Version:
dotnet list package SixLabors.ImageSharpVerify Fix Applied:
Verify the installed ImageSharp version is 3.1.7 or higher (for v3) or 2.1.10 or higher (for v2). Test GIF processing functionality works without crashes.📡 Detection & Monitoring
Log Indicators:
- Application crashes or exceptions when processing GIF files
- Stack traces containing ImageSharp.GifDecoder references
- Increased error rates in image processing endpoints
Network Indicators:
- Unusual spikes in GIF file uploads to image processing endpoints
- Large or malformed GIF files being submitted
SIEM Query:
source="application_logs" AND ("ImageSharp" OR "GifDecoder") AND ("crash" OR "exception" OR "access violation")