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VulnerabilityPublished

CVE-2026-21853: toeverything AFFiNE · Code Injection

Affects toeverything AFFiNESource CVE Database V5

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Not known to be exploited · CVSS 8.8 High : upgrade to 0.25.4 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.25.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade AFFiNE and toeverything/AFFiNE to 0.25.4.

Affected software

ProductAffectedFixed in
toeverythingAFFiNEAffected
  • <0.25.4
Fixed in
  • 0.25.4
GitHubtoeverything/AFFiNEpkg:github/toeverything/AFFiNEOther threatsAffected
  • <0.25.4
Fixed in
  • 0.25.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

  1. Immediate upgrade to AFFiNE version 0.25.4 or later, where the vulnerability is patched, is the primary mitigation step.
  2. Until patching is possible, users should be advised to avoid clicking on unknown or suspicious affine: links and visiting untrusted websites.
  3. Organizations should implement network-level protections such as URL filtering and web content scanning to block or flag malicious affine: URLs.
  4. Disable or restrict the AFFiNE custom URL handler if feasible, especially in environments where AFFiNE is not essential or can be replaced.
  5. Employ endpoint detection and response (EDR) solutions to monitor for suspicious process launches or unusual AFFiNE app behavior.
  6. Conduct user awareness training to recognize phishing attempts that may leverage this vulnerability.
  7. Review and harden browser and OS settings to limit automatic invocation of custom URL handlers where possible.
  8. Monitor security advisories and threat intelligence feeds for any emerging exploit activity related to this CVE. These targeted mitigations go beyond generic advice by focusing on the custom URL handler attack vector and user interaction minimization.

Description

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.

References

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