SecuriTricks - CVE-2026-4265

Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to validate team-specific upload_file permissions which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553

Product(s) Impacted

Vendor	Product	Versions
Mattermost	Mattermost	11.3.0, 11.2.2, 10.11.10

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-863

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	mattermost	mattermost	11.3.0	/	/	/	/	/	/	/
a	mattermost	mattermost	11.2.2	/	/	/	/	/	/	/
a	mattermost	mattermost	10.11.10	/	/	/	/	/	/	/

References

https://mattermost.com/security-updates

CVSS Score

4.3 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: LOW
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: LOW
Availability Impact: NONE

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

View Vector String

Timeline

Published: March 16, 2026, 2:20 p.m.
Last Modified: March 16, 2026, 2:53 p.m.

Status : Undergoing Analysis

CVE is currently being analyzed by NVD staff, this process results in association of reference link tags, CVSS scores, CWE association, and CPE applicability statements.

More info

Source

[email protected]

CVE-2026-4265