AFFiNE: One-click Remote Code Execution through Custom URL Handling
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-94.
Summary
AFFiNE is an open-source, all-in-one workspace and an operating system. Prior to version 0.25.4, there is a one-click remote code execution vulnerability. This vulnerability can be exploited by embedding a specially crafted affine: URL on a website. An attacker can trigger the vulnerability in two common scenarios: 1/ A victim visits a malicious website controlled by the attacker and the website redirect to the URL automatically, or 2/ A victim clicks on a crafted link embedded on a legitimate website (e.g., in user-generated content). In both cases, the browser invokes AFFiNE custom URL handler, which launches the AFFiNE app and processes the crafted URL. This results in arbitrary code execution on the victim’s machine, without further interaction. This issue has been patched in version 0.25.4.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| toeverything | AFFiNE | before 0.25.4 | 0.25.4 | Patch available | CNA |
- AFFiNE Vendortoeverything Affected before 0.25.4 Fixed in 0.25.4 Patch available CNA
Remediation
- Fix · CNA AFFiNE (toeverything) Fixed in 0.25.4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-21853
- 2026-10-28 EPSS moved to the 50th–90th percentile
References
More toeverything vulnerabilities
- TI-2026-06784 toeverything AFFiNE Public Markdown Preview Endpoint :docId allowDocPreview authorization CVSS 4.0MEDIUM 6.9
- TI-2025-10952 toeverything AFFiNE Avatar Upload Image Endpoint cross site scripting CVSS 4.0MEDIUM 5.1
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences