GHSA-6cqf-375w-639g Gitea: RSS/Atom feed handlers bypass API-token scope & public-only confinement (incomplete fix of #37698)
SummaryGitea's RSS/Atom feed handlers accept API-token Basic auth but perform **no token-scope or
public-only enforcement**. A personal access token that is correctly blocked (HTTP 403) from a
private repository on `/raw`, `/media`, `/archive`, and `/releases/download/...` — because it is
marked *public-only* or lacks the `repository` scope category — still returns that repository's
private content through the feed routes. This is a token-confinement bypass and appears to be an
incomplete fix of #37698, which added that scope enforcement to the download handlers but not to the
sibling feed handlers.This is **not** a cross-user access bug: the requesting account must still legitimately have repo
read access (`RepoAssignment` + `reqUnitCodeReader` are enforced). What is bypassed is the guarantee
that a *confined* token cannot reach private content — which is exactly the property #37698 was
shipped to provide for downloads, and which matters when such a token is handed to a third-party
service/CI, leaked, or used in a lower-trust integration.Details#37698 added `context.CheckTokenScopes` / `CheckRepoScopedToken`
(`services/context/permission.go`) to the raw / media / archive / attachment download handlers, so a
public-only or wrong-scope-category token cannot read private-repo content even when the owning user
otherwise has access.The feed handlers are registered with `webAuth.AllowBasic` (so they accept token Basic auth) but call
no scope / public-only check. A grep for `CheckTokenScopes` / `CheckRepoScopedToken` / `IsApiToken`
across `routers/web/feed/` and the release feed handlers returns nothing.Affected routes (all token-reachable via `webAuth.AllowBasic`, none call the scope check):| Route | Handler | Private data exposed |
|---|---|---|
| `GET /{owner}/{repo}.rss` / `.atom` | `repo.Home` → `handleRepoHomeFeed` (`view_home.go`) | last-10 commits: SHA, full message, author name + email |
| `GET /{owner}/{repo}/rss/branch/*`, `/atom/branch/*` | `feed.RenderBranchFeed*` → `ShowBranchFeed` (`routers/web/feed/branch.go`) | same commit data, any branch |
| `GET /{owner}/{repo}/releases.rss` / `.atom` | `ReleasesFeedRSS/Atom` (`routers/web/repo/release.go`) → `ShowReleaseFeed` | private release names, notes, descriptions |
| `GET /{owner}/{repo}/tags.rss` / `.atom` | `TagsListFeedRSS/Atom` → `ShowReleaseFeed` | private tag names + messages |
| `GET /{user}.rss` / `.atom` | `showUserFeed` (`routers/web/feed/profile.go`), `includePrivate = self \|\| admin` | the token owner's private cross-repo activity stream |Inconsistency that pins this down: the branch-feed routes sit in the **same route group** as `/raw`,
`/media`, `/archive` (all of which call `checkDownloadTokenScope`), and `releases.rss` sits next to
`/releases/attachments/{uuid}` and `/releases/download/...` (both go through `ServeAttachment` → scope
check). Only the feeds were missed. The API equivalents (`ListReleases` / `ListTags`) are scope-gated
via `tokenRequiresScopes`.Two distinct confinement bypasses:**Public-only bypass.** A token created with the *public-only* option is blocked (403) from a
private repo on `/raw`, `/archive`, `/releases/download/...`, but returns private commit / release
data via `.../releases.rss`, `.../rss/branch/*`, `/{owner}/{repo}.rss`, and the owner's private
activity via `/{user}.rss`.**Scope-category bypass.** A token scoped to only e.g. `read:issue` (no `read:repository`) is
rejected by the download handlers but reads repository commit/release content via the feeds.PoCVerified live against the official `gitea/gitea:1.26.2` Docker image (sqlite, feeds enabled).Setup: non-admin user `alice`; private repo `alice/secret` with a commit
`"SECRET-COMMIT-MARKER ..."` (file `secret.txt`) and a release `"Private Release"` / body
`"SECRET-RELEASE-MARKER ..."`. Two confined personal access tokens, both sent via HTTP Basic so the
auth method is identical across download and feed — only the route differs:Token A: scopes `["public-only", "read:repository"]`Token B: scopes `["read:issue"]`Anonymous baseline returns 404 on the repo feeds (data is genuinely private) and a marker-free 200 on
`/alice.rss` (public activity only) — confirming the leak is gated only by the missing token check.ImpactInformation disclosure of private **commit metadata** (SHA, message, author name+email),
**release/tag notes**, and the owner's **private activity stream**, to the holder of a confined token
that was specifically configured *not* to reach private content. Not raw file blobs (feeds don't
serve file contents). Requires a token belonging to an account that already has repo read access, so
the realistic threat is a leaked / shared / lower-trust token rather than an anonymous attacker —
which is precisely the threat model #37698 addressed for downloads.Suggested remediationAdd a token-scope check at the top of each feed handler, mirroring `checkDownloadTokenScope`:for `ShowBranchFeed`, `ShowRepoFeed`, `ShowFileFeed`, `ShowReleaseFeed` (repo feeds). For the user
feed, gate `includePrivate` behind a non-public-only token (or require the `user` / `repository`
scope) so a confined token can't pull private activity.
CVSS v3.1 score: 4.3