CVE-2026-33335Public exploitNetwork attack vector

Local application invocation via unvalidated external URL schemes

Published Mar 24, 2026 · Updated Mar 24, 2026

Improper URL-scheme authorization in Vikunja Desktop 0.21.0 through 2.1.0 allows remote authenticated users to invoke local applications. The setWindowOpenHandler callback passes renderer-supplied window.open URLs directly to shell.openExternal without validating or allowlisting their schemes. A collaborator must place a crafted link in shared content and persuade a Desktop user to click it; the operating system then opens a local file, application, or registered protocol handler.

CVSS severity6.4
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper URL-scheme authorization in Vikunja Desktop 0.21.0 through 2.1.0 allows remote authenticated users to invoke local applications. The setWindowOpenHandler callback passes renderer-supplied window.open URLs directly to shell.openExternal without validating or allowlisting their schemes. A collaborator must place a crafted link in shared content and persuade a Desktop user to click it; the operating system then opens a local file, application, or registered protocol handler.

The record

CVE
CVE-2026-33335
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
Vikunja
Product
Vikunja
Classifications
CWE-939, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.21.0, < 2.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Vikunja · Vikunjaversion=>= 0.21.0, < 2.2.0

Published CVSS scores

8.0NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
6.4GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-939Improper Authorization in Handler for Custom URL Scheme
T1204.001User Execution: Malicious Link

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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