CVE-2026-3115 | Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0 Group Retrieval Endpoint authorization

VDB-353683 · CVE-2026-3115 · GCVE-0-2026-3115 MATTERMOST UP TO 10.11.10/11.2.2/11.3.1/11.4.0 GROUP RETRIEVAL ENDPOINT AUTHORIZATION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 4.2 $0-$5k 1.81+ Summaryinfo A vulnerability, which was classified as problematic, has been found in Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0. Affected by this vulnerability is an unknown functionality of the component Group Retrieval Endpoint. This manipulation causes authorization. This vulnerability appears as CVE-2026-3115. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component. Detailsinfo A vulnerability classified as problematic was found in Mattermost up to 10.11.10/11.2.2/11.3.1/11.4.0. Affected by this vulnerability is an unknown functionality of the component Group Retrieval Endpoint. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. 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. As an impact it is known to affect confidentiality. The summary by CVE is: Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594 The weakness was presented by winfunc. It is possible to read the advisory at mattermost.com. This vulnerability is known as CVE-2026-3115 since 02/24/2026. The exploitation appears to be easy. The attack can be launched remotely. The technical details are unknown and an exploit is not publicly available. Upgrading to version 10.11.11, 11.2.3, 11.3.2, 11.4.1 or 11.5.0 eliminates this vulnerability. Productinfo Type Groupware Software Name Mattermost Version 10.11.0 10.11.1 10.11.2 10.11.3 10.11.4 10.11.5 10.11.6 10.11.7 10.11.8 10.11.9 10.11.10 11.0 11.1 11.2 11.2.0 11.2.1 11.2.2 11.3 11.3.0 11.3.1 11.4.0 License open-source CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 4.3 VulDB Meta Temp Score: 4.2 VulDB Base Score: 4.3 VulDB Temp Score: 4.1 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 4.3 CNA Vector (Mattermost): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Authorization CWE: CWE-863 / CWE-285 / CWE-266 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Mattermost 10.11.11/11.2.3/11.3.2/11.4.1/11.5.0 Timelineinfo 02/24/2026 CVE reserved 03/26/2026 +30 days Advisory disclosed 03/26/2026 +0 days VulDB entry created 03/26/2026 +0 days VulDB entry last update Sourcesinfo Advisory: mattermost.com Researcher: winfunc Status: Confirmed CVE: CVE-2026-3115 (🔒) GCVE (CVE): GCVE-0-2026-3115 GCVE (VulDB): GCVE-100-353683 Entryinfo Created: 03/26/2026 19:02 Changes: 03/26/2026 19:02 (64) Complete: 🔍 Cache ID: 99:5AC:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸