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Fencer Vulns
high 8.8

CVE-2026-21853 json

AFFiNE: One-click Remote Code Execution through Custom URL Handling

published 2026-03-02 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-9252

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

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.

Patch / fix

  • affine affine 0.25.4

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
8 mo ago

Exploit prediction

0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/toeverything/AFFiNE/security/advisories/GHSA-67vm-2mcj-8965 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • toeverything AFFiNE

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.