RCE in Affine
CVE-2026-21853
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.
Vulnerability class: RCE (Remote Code Execution)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000
Affected products
- Affine
- Toeverything Affine — versions < 0.25.4
Weakness classification (CWE)
References
- github.com/toeverything/AFFiNE/security/advisories/GHSA-67vm-2mcj-8965 (Exploit, Third Party Advisory)
- github.com/toeverything/AFFiNE/pull/13864 (Patch)
- github.com/toeverything/AFFiNE/commit/c9a4129a3e9376b688c18e1dcd6c87a775caac80 (Patch)
Frequently asked questions
- What is CVE-2026-21853?
- CVE-2026-21853 is a high-severity vulnerability in Affine, classified under Code Injection. CVSS score: 8.8/10. Published 2026-03-02.
- How severe is CVE-2026-21853?
- High severity. CVSS v3 base score is 8.8 out of 10.