CVE-2026-27769 | Mattermost up to 10.11.12/11.4.x Conntexted Workspaces Feature authorization

VDB-357713 · CVE-2026-27769 · GCVE-0-2026-27769 MATTERMOST UP TO 10.11.12/11.4.X CONNTEXTED WORKSPACES FEATURE AUTHORIZATION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 2.7 $0-$5k 3.46 Summaryinfo A vulnerability classified as problematic has been found in Mattermost up to 10.11.12/11.4.x. This issue affects some unknown processing of the component Conntexted Workspaces Feature. The manipulation leads to authorization. This vulnerability is listed as CVE-2026-27769. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component. Detailsinfo A vulnerability was found in Mattermost up to 10.11.12/11.4.x. It has been rated as problematic. This issue affects some unknown processing of the component Conntexted Workspaces Feature. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Impacted is integrity. The summary by CVE is: Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API.. Mattermost Advisory ID: MMSA-2026-00603 The weakness was presented by daw10. The advisory is shared at mattermost.com. The identification of this vulnerability is CVE-2026-27769 since 03/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are necessary for exploitation. Neither technical details nor an exploit are publicly available. Upgrading to version 10.11.13 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 10.11.11 10.11.12 11.0 11.1 11.2 11.3 11.4 License open-source CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 2.7 VulDB Meta Temp Score: 2.7 VulDB Base Score: 2.7 VulDB Temp Score: 2.6 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 2.7 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-862 / CWE-863 / CWE-285 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 10.11.13/11.5.0 Timelineinfo 03/16/2026 CVE reserved 04/15/2026 +29 days Advisory disclosed 04/15/2026 +0 days VulDB entry created 04/15/2026 +0 days VulDB entry last update Sourcesinfo Advisory: mattermost.com Researcher: daw10 Status: Confirmed CVE: CVE-2026-27769 (🔒) GCVE (CVE): GCVE-0-2026-27769 GCVE (VulDB): GCVE-100-357713 Entryinfo Created: 04/15/2026 14:02 Changes: 04/15/2026 14:02 (64) Complete: 🔍 Cache ID: 99:360:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸