How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
- Attack vector: Network — reachable from anywhere that can route to the service.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: Low — an ordinary user account is enough.
- User interaction: Required — someone has to click, open or visit something.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: High — total loss, or loss the attacker controls.
- Integrity impact: High — total loss, or loss the attacker controls.
- Availability impact: High — total loss, or loss the attacker controls.
Weakness class
CVE-2026-33335 is classified as CWE-939: Improper Authorization in Handler for Custom URL Scheme. The product uses a handler for a custom URL scheme, but it does not properly restrict which actors can invoke the handler using the scheme.
Affected software
CVE-2026-33335 is recorded against 1 package.
- vikunja (from 0.21.0 up to 2.2.2)
Timeline and source
Published on 24 March 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.
References
github.com
vikunja.io
github.com
Other advisories for this package
vikunja has other advisories on record. If you are patching this one, these are worth checking on the same host:
Same weakness in other software
These advisories are the same class of weakness (CWE-939: Improper Authorization in Handler for Custom URL Scheme) in other software:
