CVE-2026-2458

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-4265 Guest user can upload files without permission across teams

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 uploadfile permissions which allows a guest user to post files in channels where they lack uploadfile permission via uploading files in a team where they have permission and reusing the file...

CVE-2026-4265

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 uploadfile permissions which allows a guest user to post files in channels where they lack uploadfile permission via uploading files in a team where they have permission and reusing the file...

CVE-2026-4265

Mattermost CVE-2026-4265 affects Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x

CVE-2026-4265 Guest user can upload files without permission across teams

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 uploadfile permissions which allows a guest user to post files in channels where they lack uploadfile permission via uploading files in a team where they have permission and reusing the file...

CVE-2026-4265 Guest user can upload files without permission across teams

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 uploadfile permissions which allows a guest user to post files in channels where they lack uploadfile permission via uploading files in a team where they have permission and reusing the file...

CVE-2026-2458

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-2458 Unauthorized channel enumeration in private teams after member removal

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate team membership when searching channels which allows a removed team member to enumerate all public channels within a private team via the channel search API endpoint.. Mattermost Advisory ID:...

CVE-2026-2463 Unauthorized access to invite ID during team creation

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to filter invite IDs based on user permissions, which allows regular users to bypass access control restrictions and register unauthorized accounts via leaked invite IDs during team creation.. Mattermost Advisory ID:...

CVE-2026-2463

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to filter invite IDs based on user permissions, which allows regular users to bypass access control restrictions and register unauthorized accounts via leaked invite IDs during team creation.. Mattermost Advisory ID:...

CVE-2026-2463 Unauthorized access to invite ID during team creation

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to filter invite IDs based on user permissions, which allows regular users to bypass access control restrictions and register unauthorized accounts via leaked invite IDs during team creation.. Mattermost Advisory ID:...

CVE-2026-2463

CVE-2026-2463 affects Mattermost up to versions 11.3.0, 11.2.2, and 10.11.10. The issue arises because invite IDs are not properly filtered by user permissions during team creation, allowing regular users to bypass access controls and register unauthorized accounts via leaked invite IDs. The vuln...

CVE-2026-2463 Unauthorized access to invite ID during team creation

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to filter invite IDs based on user permissions, which allows regular users to bypass access control restrictions and register unauthorized accounts via leaked invite IDs during team creation.. Mattermost Advisory ID:...

PT-2026-25813

Mattermost versions 10.11.x = 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.3.0 and earlier 11.3.x series, 11.2.2 and earlier 11.2.x series, as well as 10.11.10 and earlier 10.11.x series, have security vulnerabilities. These vulnerabilities...

PT-2026-25684

Mattermost allows a removed team member to enumerate all public channels within a private team in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causi...

PT-2026-25705

Mattermost fails to validate team-specific upload file permissions in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causing false-positive reports fr...

Mattermost 安全漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.3.0 and earlier 11.3.x series, 11.2.2 and earlier 11.2.x series, as well as 10.11.10 and earlier 10.11.x series, have security vulnerabilities. These vulnerabilities...

PT-2026-25679

Mattermost fails to filter invite IDs based on user permissions in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. If this is causing false-positive reports from...

How Vulnerable Are AI Agents to Indirect Prompt Injections? Insights from a Large-Scale Public Competition

LLM based agents are increasingly deployed in high stakes settings where they process external data sources such as emails, documents, and code repositories. This creates exposure to indirect prompt injection attacks, where adversarial instructions embedded in external content manipulate agent...