PT-2026-63306 · Go · Gitea.Dev

CVE-2026-58440

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Published

2026-07-21

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Updated

2026-07-21

CVSS v3.1

6.8

Medium

VectorAV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Affected product

Gitea — services/repository/collaboration.go (DeleteCollaboration) + webhook delivery

Summary

When a collaborator with admin permission on a private repo creates a webhook, that webhook keeps firing after the collaborator's access is revoked. Gitea's revocation cleanup DeleteCollaboration removes the collaboration record, recalculates accesses, drops watches, and unassigns issues — but it does not remove or disable webhooks the user created, and webhook delivery never re-checks whether the creator still has repo access. The former collaborator therefore receives the full payload (issue/comment bodies, commit data) of all future repository events at their controlled endpoint, indefinitely and invisibly.

Affected code

  • services/repository/collaboration.go → DeleteCollaboration() — cleans watches/assignees only; no webhook cleanup.
  • Webhook delivery path — fires on repo events without re-validating the creator's current access.

Steps to reproduce

Using the provided reproduction materials:
  1. Attacker (admin collaborator) creates a webhook → revoke access.
  2. Control: GET /api/v1/repos/admin/wh-repo (attacker) → 404.
  3. GET .../hooks → webhook still active=true.
  4. Admin creates a new issue after revocation → the catcher receives action:"opened", issue.title:"CRITICAL SECRET: …", issue.body (sentinel private key), repository.private:true. (Runtime-confirmed on gitea/gitea:1.25.4. Catcher is an internal sentinel listener; the payload is a planted sentinel, not real data; nothing is sent to any external/metadata endpoint.)

Impact

Authenticated former admin-collaborator → ongoing real-time exfiltration of private content created after revocation; invisible to the owner; scope crosses from the application boundary to data the user should no longer access.

Suggested remediation

  1. On revocation, delete/disable webhooks created by the removed collaborator (or hand them to the owner).
  2. Re-validate the creator's current repo access before each webhook delivery.
  3. At minimum, warn admins on revocation if the user created webhooks.

Credit

Reported as part of an incomplete-patch / authorization-residue measurement study (responsible disclosure).

Fix

Incorrect Authorization

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Weakness Enumeration

CWE-863

Related Identifiers

CVE-2026-58440
GHSA-66M4-5JJR-2RG5

Affected Products

Gitea.Dev