PT-2026-42745

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs...

PT-2026-42748

Mattermost versions 11.6.x = 11.6.0, 11.5.x = 11.5.3, 11.4.x = 11.4.4, 10.11.x = 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID:...

CVE-2026-6333 SSRF via Host Header Spoofing in Custom Slash Commands

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost...

EUVD-2026-30751

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 fail to check public/private permissions which allows members without these permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591...

SUSE CVE-2026-26233

Mattermost versions 11.4.x = 11.4.0, 11.3.x = 11.3.1, 11.2.x = 11.2.3, 10.11.x = 10.11.11 fail to rate limit login requests which allows unauthenticated remote attackers to cause denial of service server crash and restart via HTTP/2 single packet attack with 100+ parallel login requests...

EUVD-2026-12516

Mattermost versions 10.11.x = 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-0058...

EUVD-2026-12415

Mattermost versions 11.3.x = 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579...

CVE-2026-25783

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586...

CVE-2026-26246 Memory Exhaustion via Malformed PSD File Upload

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to bound memory allocation when processing PSD image files which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted PSD file. Mattermost Advisory I...

PT-2026-25809

Mattermost versions 11.3.x = 11.3.0, 11.2.x = 11.2.2, 10.11.x = 10.11.10 fail to handle incorrectly reported array lengths which allows malicious user to cause OOM errors and crash the server via sending corrupted msgpack frames within websocket messages to calls plugin. Mattermost Advisory ID:...

Time-of-check Time-of-use (TOCTOU) Race Condition

Overview Affected versions of this package are vulnerable to Time-of-check Time-of-use TOCTOU Race Condition via a race condition in the /commonteams API endpoint. An attacker can gain unauthorized access to team names by exploiting the timing of channel membership validation during data retrieva...

EUVD-2025-186557

Mattermost versions 11.0 fail to properly enforce the "Allow users to view archived channels" setting which allows regular users to access archived channel content and files via the "Open in Channel" functionality from followed threads...

EUVD-2024-38242

Malicious code in bioql PyPI...

EUVD-2024-2498

Malicious code in bioql PyPI...

EUVD-2025-29172

Malicious code in bioql PyPI...

EUVD-2022-42571

Malicious code in bioql PyPI...

EUVD-2022-6058

Malicious code in bioql PyPI...

EUVD-2023-59297

Malicious code in bioql PyPI...

EUVD-2022-6283

Malicious code in bioql PyPI...

CVE-2024-1949

A race condition in Mattermost versions 8.1.x before 8.1.9, and 9.4.x before 9.4.2 allows an authenticated attacker to gain unauthorized access to individual posts' contents via carefully timed post creation while another user deletes posts...