CVE-2026-21853
📋 TL;DR
This CVE describes a one-click remote code execution vulnerability in AFFiNE workspace software. Attackers can exploit it by tricking users into visiting malicious websites or clicking crafted links, leading to arbitrary code execution on the victim's machine without further interaction. All AFFiNE users running versions prior to 0.25.4 are affected.
💻 Affected Systems
- AFFiNE
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of victim's system with full remote code execution, allowing data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Attacker gains initial foothold on victim's machine, potentially leading to credential theft, lateral movement, or data exfiltration.
If Mitigated
Limited impact if proper network segmentation, endpoint protection, and user awareness training are implemented.
🎯 Exploit Status
One-click exploitation via crafted URLs makes this easily weaponizable. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.25.4
Vendor Advisory: https://github.com/toeverything/AFFiNE/security/advisories/GHSA-67vm-2mcj-8965
Restart Required: Yes
Instructions:
1. Download AFFiNE version 0.25.4 or later from official sources. 2. Install the update. 3. Restart the application.
🔧 Temporary Workarounds
Disable AFFiNE URL handler
allRemove or disable the affine: URL protocol handler registration to prevent automatic application launch
Windows: reg delete HKCU\Software\Classes\affine /f
macOS: defaults delete com.affine.app
Linux: Remove affine.desktop file from ~/.local/share/applications/
Use web version only
allSwitch to using AFFiNE web version instead of desktop application
🧯 If You Can't Patch
- Implement network filtering to block malicious domains and restrict user access to untrusted websites
- Deploy endpoint protection with behavior monitoring to detect and block suspicious process execution
🔍 How to Verify
Check if Vulnerable:
Check AFFiNE version in application settings or via command line: affine --versionCheck Version:
affine --versionVerify Fix Applied:
Confirm version is 0.25.4 or higher and test that affine: URLs are properly validated📡 Detection & Monitoring
Log Indicators:
- Unusual process execution from AFFiNE
- Suspicious affine: URL invocations
- AFFiNE launching with unexpected parameters
Network Indicators:
- Outbound connections from AFFiNE to unknown domains
- DNS requests for suspicious domains following affine: URL access
SIEM Query:
process_name:"AFFiNE" AND (command_line:"*affine:*" OR parent_process:chrome.exe)