Nixpkgs security tracker

Untriaged

Permalink CVE-2026-27656

5.7 MEDIUM

CVSS version (CVSS): 3.1
Attack Vector (AV): Network (N)
Attack Complexity (AC): High (H)
Privileges Required (PR): High (H)
User Interaction (UI): Required (R)
Scope (S): Unchanged (U)
Confidentiality (C): High (H)
Integrity (I): High (H)
Availability (A): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): High (H)
Modified Privileges Required (MPR): High (H)
Modified User Interaction (MUI): Required (R)
Modified Confidentiality (MC): High (H)
Modified Scope (MS): Unchanged (U)
Modified Integrity (MI): High (H)
Modified Availability (MA): None (N)

created 2 months, 3 weeks ago Activity log

Created suggestion 2 months, 3 weeks ago

Account Takeover via Substring Matching in OpenID Connect Authentication

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 properly validate user identity in the OpenID {{IsSameUser()}} comparison logic, which allows an attacker to take over arbitrary user accounts via an overly permissive substring matching flaw in the user discovery flow.. Mattermost Advisory ID: MMSA-2026-00590