CVE-2026-24791: Gitea: Public-only tokens bypass private-resource restrictions on `/api/v1/user` self routes

Many authenticated self routes under /api/v1/user/... do not enforce the public-only token restriction. As a result, a token or OAuth grant marked public-only, but otherwise carrying the route-required read/write scope category, can access or modify private account resources through self routes.

The canonical private-user endpoint correctly rejects the same tokens, for example GET /api/v1/users/{privateUser} returns 403. The bypass exists because the generic /api/v1/user route group requires user scope and reqToken(), but does not enforce the token’s public-only restriction for most self routes.

This is a systemic token/OAuth scope-boundary bypass, not a single endpoint bug.

This appears related to the previously fixed public-only token issue tracked as CVE-2025-68941 / GHSA-xfq3-qj7j-4565, which affected Gitea < 1.22.3. The behavior described here reproduces on tested main checkout 6a2706626904. A representative SSH-key self-route PoC also reproduces on tested releases through v1.26.1. In other words, this should be treated as an incomplete fix / residual gap in a different route family, not as a duplicate of the older advisory.