Description
Nextcloud Deck is a kanban style organization tool aimed at personal planning and project organization for teams integrated with Nextcloud. Prior to 1.12.7, 1.14.4, and 1.15.1, file extension can be spoofed by using RTLO characters, tricking users into download files with a different extension than what is displayed. This vulnerability is fixed in 1.12.7, 1.14.4, and 1.15.1.
Affected products
nextcloud: deck
References4
- github.com/nextcloud/security-advisories/security/advisories/GH… PatchVendor Advisory
- hackerone.com/reports/2326618 Permissions RequiredVendor Advisory
- github.com/nextcloud/deck/commit/afa95d3c507465b9d31af7c88c69b7… Patch
- github.com/nextcloud/deck/pull/6671 Issue Tracking
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 6 · as of 11 November 2026
- CWE
- CWE-116
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.