Arbitrary file read via block duplication in Mattermost Boards
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate input when patching and duplicating a board, which allows a user to read any arbitrary file on the system via duplicating a specially crafted block in Boards.
02 / AFFECTED SOFTWARE
Affected packages
42 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate input when patching and duplicating a board, which allows a user to read any arbitrary file on the system via duplicating a specially crafted block in Boards.
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate input when patching and duplicating a board, which allows a user to read any arbitrary file on the system via duplicating a specially crafted block in Boards.
Mattermost allows reading arbitrary files in github.com/mattermost/mattermost-server
05 / REFERENCES
Further evidence
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/20xxx/CVE-2025-20051.json
- https://mattermost.com/security-updates
- https://nvd.nist.gov/vuln/detail/CVE-2025-20051
- https://github.com/mattermost/mattermost
- https://github.com/mattermost/mattermost-plugin-boards/commit/025ce8d363a054473bc002f43f602a4032d38c06
- https://github.com/mattermost/mattermost/commit/4ed702ccff4ec3c9eff832a9b6060f9f4454141d
- https://github.com/advisories/GHSA-v469-7wp6-7cvp