Overview
CVE-2025-2615 describes a medium severity vulnerability affecting GitLab Community Edition (CE) and Enterprise Edition (EE). This vulnerability allows a blocked user to potentially bypass access restrictions and access sensitive information by establishing GraphQL subscriptions through WebSocket connections. The issue has been addressed in GitLab versions 18.3.6, 18.4.4, and 18.5.2. This article provides a detailed analysis of the vulnerability, its impact, and the necessary steps to mitigate it.
Technical Details
The vulnerability stems from insufficient access control checks during the processing of GraphQL subscriptions established via WebSocket connections. Even after a user is blocked from accessing GitLab resources, pre-existing WebSocket connections might remain active, potentially allowing the blocked user to continue receiving data through GraphQL subscriptions if appropriate security measures are not implemented. This flaw could expose sensitive information to unauthorized users.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) score for CVE-2025-2615 is 4.3, indicating a MEDIUM severity. The CVSS vector is likely AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. This translates to:
- Attack Vector (AV): Network (N) – The vulnerability is exploitable over a network.
- Attack Complexity (AC): Low (L) – The vulnerability is relatively easy to exploit.
- Privileges Required (PR): None (N) – No privileges are required to exploit the vulnerability. In this case, blocked user has the pre-existing connection.
- User Interaction (UI): None (N) – No user interaction is required to exploit the vulnerability.
- Scope (S): Unchanged (U) – The vulnerability affects the security of the same component.
- Confidentiality Impact (C): Low (L) – There is limited impact on data confidentiality. Sensitive data could be disclosed.
- Integrity Impact (I): None (N) – There is no impact on data integrity.
- Availability Impact (A): None (N) – There is no impact on system availability.
Possible Impact
The exploitation of CVE-2025-2615 could lead to the following:
- Information Disclosure: Blocked users could potentially access sensitive information through pre-existing GraphQL subscriptions, violating access control policies.
- Privilege Escalation (Limited): While not directly escalating privileges in the traditional sense, a blocked user retains access to some information they should no longer have.
Mitigation or Patch Steps
To mitigate the risk associated with CVE-2025-2615, GitLab administrators are strongly advised to upgrade to one of the following patched versions:
- Upgrade to version 18.3.6 or later if you are using the 18.3.x series.
- Upgrade to version 18.4.4 or later if you are using the 18.4.x series.
- Upgrade to version 18.5.2 or later if you are using the 18.5.x series.
- Alternatively, upgrade to the latest available GitLab version to receive all the latest security updates and features.
After upgrading, ensure proper invalidation of WebSocket connections for blocked users to prevent unauthorized access. Monitor GitLab logs for any suspicious activity related to GraphQL subscriptions.
