Gitea: GHSA-8fwc-qjw5-rvgp ClearRepoWatches fix not applied to API EditRepo path — sister code path retains stale watches on public->private

Summary

GHSA-8fwc-qjw5-rvgp ("Gitea may send release notification emails for private repositories to users whose access has been revoked", fix in PR #36319 / commit 8a98ac22) added repo_model.ClearRepoWatches as a defense for the state transition public→private. The cleanup was wired into services/repository/repository.go::MakeRepoPrivate only. The sister helper services/repository/repository.go::updateRepository — which is the function used by the API path PATCH /api/v1/repos/{owner}/{repo} — was not patched and still calls ClearRepoStars only.

As a result, when a public repository is flipped to private via the REST API (rather than via the web Settings → Danger Zone UI), the watch records persist. Affected users can:

• See the now-private repository in GET /api/v1/user/subscriptions?private=true along with its full Repository JSON (description, default branch, language, fork status, counts, mirror metadata, license list, etc.) — even though they have no access to the repository.
• Have their stale watch records re-leak content through any future notification path that does not include the send-time CheckRepoUnitUser check that was added to services/mailer/mail_release.go.
• Inflate the visible NumWatches counter on the repository.

Severity

Medium — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Same impact class as the original GHSA-8fwc-qjw5-rvgp (which was classified Medium). The send-time mail filter added in the same PR mitigates the release-content disclosure vector. The residual leak is repo metadata via the subscriptions endpoint and stale watcher counts.

CWE-281 (Improper Preservation of Permissions), CWE-359 (Exposure of Private Personal Information), CWE-200 (Exposure of Sensitive Information).

Affected Versions

Every release starting from v1.25.4 (the release shipping the original GHSA-8fwc-qjw5-rvgp fix) through HEAD (master @ ef801bb6, 2026-05-16). The follow-up refactor in commit 943ff752 (PR #36959, 2026-03-24) which merged MakeRepoPublic+MakeRepoPrivate did not propagate the ClearRepoWatches call to updateRepository.

Affected Component

• services/repository/repository.go:240-302 — func updateRepository(ctx, repo, visibilityChanged bool), the sister helper called via the API path. Clears stars on line 273 but never calls ClearRepoWatches.
• routers/api/v1/repo/repo.go::Edit (line 573) → updateBasicProperties (line 678-697) → repo_service.UpdateRepository(ctx, repo, visibilityChanged) (line 726) — the API path that exercises the sister helper.

Steps to Reproduce

The bug is observable purely from static analysis; the live PoC is straightforward.

1. Start a Gitea instance at any release from v1.25.4 onwards (verified static at HEAD ef801bb6).

2. Create users A (org admin) and B (member). Create a public repository A/proj. As B, watch the repo:

   curl -u B:<token> -X PUT "https://gitea.example.com/api/v1/repos/A/proj/subscription"
   

3. As A, flip the repo to private via the REST API (not via the web UI):

   curl -u A:<token> -X PATCH "https://gitea.example.com/api/v1/repos/A/proj" \
        -H 'Content-Type: application/json' \
        -d '{"private": true}'
   

4. As B, list B's watched repos with private=true:

   curl -u B:<token> "https://gitea.example.com/api/v1/user/subscriptions"
   

   The now-private repo A/proj is returned in B's subscription list, with the full Repository payload — including description, default_branch, language, topics, license, fork/branch/issue/release counts, etc.

5. Compare with the web-UI path (which IS patched). As A, flip a different public repo A/proj2 to private via Settings → Danger Zone → "Make this repository private" (which calls repo_service.MakeRepoPrivate). Verify B's subscription list no longer contains A/proj2.

The asymmetry of outcomes between steps 4 and 5 — for the same state transition — is the gap.

Direct Evidence (no PoC needed)

$ gh api repos/go-gitea/gitea/contents/services/repository/repository.go \
    --jq .content | base64 -d | grep -n "ClearRepoWatches\|ClearRepoStars" 

154:                  if err = repo_model.ClearRepoStars(ctx, repo.ID); err != nil {
157:                  if err = repo_model.ClearRepoWatches(ctx, repo.ID); err != nil {  # MakeRepoPrivate
273:                  if err = repo_model.ClearRepoStars(ctx, repo.ID); err != nil {  # updateRepository — ClearRepoWatches missing here

The fix-author's own test file confirms the asymmetry:

$ gh api repos/go-gitea/gitea/contents/services/repository/repository_test.go --jq .content | base64 -d | grep -n "Test.*VisibilityChanged\|Test.*ClearsWatches"

44:func TestUpdateRepositoryVisibilityChanged(t *testing.T) {     # only checks act.IsPrivate
73:func TestMakeRepoPrivateClearsWatches(t *testing.T) {           # checks watches are cleared

TestUpdateRepositoryVisibilityChanged explicitly calls updateRepository(ctx, repo, true) (line 53) and asserts act.IsPrivate (line 61) — but never verifies GetRepoWatchersIDs returns empty, while the parallel TestMakeRepoPrivateClearsWatches does. The test asymmetry mirrors the fix asymmetry.

Impact

• An organization that uses terraform-gitea or any other REST-API-driven automation to flip repositories private (the canonical IaC pattern) hits updateRepository, not MakeRepoPrivate.
• An organization using the official Gitea SDK (go-sdk, py-gitea, etc.) or curl scripts to make repos private after an internal policy change hits the same path.
• Multi-tenant Gitea-as-a-service operators with API-driven repository-lifecycle endpoints are exposed.

Stale watch rows leak through GET /user/subscriptions (with the watcher's own credentials), GET /repos/{owner}/{repo}/subscribers (stale NumWatches total), and become a re-leak surface for any future notification path that forgets the send-time access check.

Suggested Fix

Drop-in mirror of the call already present in MakeRepoPrivate. In services/repository/repository.go::updateRepository, inside the existing if repo.IsPrivate { ... } branch (around line 265-276), add the ClearRepoWatches call directly after ClearRepoStars:

// services/repository/repository.go
func updateRepository(ctx context.Context, repo *repo_model.Repository, visibilityChanged bool) (err error) {
    ...
    if visibilityChanged {
        ...
        // If repo has become private, we need to set its actions to private.
        if repo.IsPrivate {
            _, err = e.Where("repo_id = ?", repo.ID).Cols("is_private").Update(&activities_model.Action{
                IsPrivate: true,
            })
            if err != nil {
                return err
            }

            if err = repo_model.ClearRepoStars(ctx, repo.ID); err != nil {
                return err
            }

            // Match MakeRepoPrivate's behavior — see PR #36319 / GHSA-8fwc-qjw5-rvgp.
            // Stale watch rows on a now-private repo leak repository metadata to ex-watchers
            // via GET /user/subscriptions?private=true and through any future notification
            // path that does not have a send-time access check.
            if err = repo_model.ClearRepoWatches(ctx, repo.ID); err != nil {
                return err
            }
        }
        ...
    }
    ...
}

Regression test (mirror of TestMakeRepoPrivateClearsWatches) to add to services/repository/repository_test.go:

func TestUpdateRepositoryClearsWatchesOnVisibilityChange(t *testing.T) {
    assert.NoError(t, unittest.PrepareTestDatabase())

    repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
    assert.False(t, repo.IsPrivate)

    watchers, err := repo_model.GetRepoWatchersIDs(t.Context(), repo.ID)
    require.NoError(t, err)
    require.NotEmpty(t, watchers)

    repo.IsPrivate = true
    assert.NoError(t, updateRepository(t.Context(), repo, true))

    watchers, err = repo_model.GetRepoWatchersIDs(t.Context(), repo.ID)
    assert.NoError(t, err)
    assert.Empty(t, watchers)

    updatedRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repo.ID})
    assert.Zero(t, updatedRepo.NumWatches)
}

Optional belt-and-suspenders: an integration test against PATCH /api/v1/repos/{owner}/{repo} with body {"private": true} that exercises the entire API path through routers/api/v1/repo/repo.go::Edit.

Discovery Methodology

This finding follows the "sister-fix-incomplete" lens that has been productive across several recent reports: pick a recent advisory where the fix lands as a single PR touching one function, then grep the codebase for parallel call sites that should have received the same defense.

For Gitea:

1. Enumerate recent advisories via gh api graphql ... securityVulnerabilities(ecosystem: GO, package: code.gitea.io/gitea).
2. GHSA-8fwc-qjw5-rvgp stood out because the description names a state transition (public→private) — a class of bug where the defense is typically wired into a single helper.
3. gh api repos/.../commits/8a98ac221 --jq '.files[] | .filename' listed the fix files; ClearRepoWatches was added to one function.
4. grep -rn "ClearRepoWatches\|MakeRepoPrivate" revealed two functions in services/repository/repository.go that handle the state transition: MakeRepoPrivate (patched) and the lowercase sister updateRepository (unpatched).
5. Walked the call chain from routers/api/v1/repo/repo.go::Edit to confirm the API path uses updateRepository, not MakeRepoPrivate.

Pre-emptive rebuttals

• "The send-time filter in MailNewRelease already blocks release-content disclosure" — Correct, and acknowledged. The residual leak this report concerns is metadata via the GET /user/subscriptions endpoint and stale NumWatches. The send-time filter is a necessary but not sufficient defense; the ClearRepoWatches call is the persistence-side belt-and-suspenders that the original PR author explicitly added.
• "The web UI is the supported path; the API path is not in scope" — The API is documented public surface (swagger spec in templates/swagger/v1_json.tmpl), Gitea ships official SDKs (go-sdk, py-gitea) that use exactly this path, and there is an official Terraform provider that exercises it. The existing fix is in a sister helper used by both paths' upstream helper — the fix author plainly intended to defend both.
• "AccessMode is None in the subscription response, so the client should infer no-access" — The response still returns the full Repository payload including description, default branch, language, fork status, counts, mirror metadata, OriginalURL, license, etc. (see services/convert/repository.go::innerToRepo line 189-259). AccessMode: 0 does not gate the metadata fields, only the Permissions{Admin,Push,Pull} triple.

References

• GHSA-8fwc-qjw5-rvgp — the original advisory: https://github.com/go-gitea/gitea/security/advisories/GHSA-8fwc-qjw5-rvgp
• PR #36319 "clean watches when make a repository private and check permission when send release emails" (commit 8a98ac221)
• PR #36959 "Require additional user confirmation for making repo private" (commit 943ff7523) — the later refactor that did not propagate the cleanup
• Patched function: services/repository/repository.go::MakeRepoPrivate (line 125, calls ClearRepoWatches line 157)
• Unpatched sister: services/repository/repository.go::updateRepository (line 240, calls only ClearRepoStars line 273)
• API entry: routers/api/v1/repo/repo.go::Edit → updateBasicProperties → repo_service.UpdateRepository → updateRepository
• Test asymmetry: services/repository/repository_test.go::TestMakeRepoPrivateClearsWatches (covered) vs TestUpdateRepositoryVisibilityChanged (does not assert watches cleared)