Summary
Gitea: Webhooks created by a collaborator keep firing after their repo access is revoked → ongoing real-time exfiltration of private repo content
Affected product
Gitea, services/repository/collaboration.go (DeleteCollaboration) + webhook delivery
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:
- Attacker (admin collaborator) creates a webhook → revoke access.
- Control:
GET /api/v1/repos/admin/wh-repo(attacker) → 404. GET .../hooks→ webhook stillactive=true.- 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 ongitea/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.)
Suggested remediation
- On revocation, delete/disable webhooks created by the removed collaborator (or hand them to the owner).
- Re-validate the creator's current repo access before each webhook delivery.
- 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).
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.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-58440 has a CVSS score of 6.8 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.27.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-58440? CVE-2026-58440 is a medium-severity incorrect authorization vulnerability in gitea.dev (go), affecting versions < 1.27.0. It is fixed in 1.27.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-58440? CVE-2026-58440 has a CVSS score of 6.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of gitea.dev are affected by CVE-2026-58440? gitea.dev (go) versions < 1.27.0 is affected.
- Is there a fix for CVE-2026-58440? Yes. CVE-2026-58440 is fixed in 1.27.0. Upgrade to this version or later.
- Is CVE-2026-58440 exploitable, and should I be worried? Whether CVE-2026-58440 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-58440 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-58440? Upgrade
gitea.devto 1.27.0 or later.