CVE-2026-55982
CVE-2026-55982 is a Information Exposure vulnerability in code.gitea.io/gitea. O3 Security confirms whether CVE-2026-55982 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gitea: OIDC userinfo Endpoint Returns Identity Claims Without Enforcing API Token Scopes
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55982.
Real-World Exposure
code.gitea.io/giteaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The OIDC userinfo endpoint (GET /login/oauth/userinfo) accepts Gitea API tokens as bearer credentials but does not enforce API token scopes before returning identity claims.
A personal access token scoped only to read:misc can successfully retrieve user information from the OIDC userinfo endpoint, even though the same token is denied access to user-related REST API endpoints that enforce scope checks.
As a result, identity information remains accessible through the OIDC endpoint regardless of the scopes assigned to the API token.
Details
Gitea supports scoped personal access tokens and enforces scope checks on user-related REST API endpoints.
For example, a token scoped only to read:misc is denied access to endpoints such as:
| Endpoint | Required Scope |
|---|---|
GET /api/v1/user | read:user |
GET /api/v1/user/emails | read:user |
GET /api/v1/user/orgs | read:organization |
Requests to these endpoints return:
403 Forbidden
with a scope-related error.
However, the same read:misc token can be supplied as a bearer credential to:
GET /login/oauth/userinfo
Authorization: Bearer <token>
and receives a successful response containing identity claims.
Observed claims include:
emailgroups
The groups claim contains organization and team membership information associated with the authenticated user.
This behavior indicates that the OIDC userinfo endpoint accepts API tokens but does not apply scope restrictions before returning identity claims.
PoC
PoC Details
Proof-of-concept code: https://anonymous.4open.science/r/Gitea_PoC-EC93/3_poc_oidc_userinfo_scope_bypass
Reproduction Steps
- Create a personal access token with only the following scope:
read:misc
- Verify that the token cannot access user-related REST API endpoints:
GET /api/v1/user
GET /api/v1/user/emails
GET /api/v1/user/orgs
Each request returns:
403 Forbidden
- Send the same token to the OIDC userinfo endpoint:
GET /login/oauth/userinfo
Authorization: Bearer <read-misc-token>
- Observe that the request succeeds and returns identity claims, for example:
{
"email": "[email protected]",
"groups": [
...
]
}
Impact
Holders of narrowly scoped API tokens can obtain identity information through the OIDC userinfo endpoint regardless of the scopes assigned to the token.
The issue does not provide access to repositories, issues, pull requests, administrative functionality, or data belonging to other users.
Impact is limited to disclosure of identity information associated with the authenticated user. However, it weakens the authorization boundary established by API token scopes because identity claims remain accessible even when the token lacks user- or organization-related scopes.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | code.gitea.io/gitea | all versions | 1.27.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for code.gitea.io/gitea. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update code.gitea.io/gitea to 1.27.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55982 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55982 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-55982. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55982 in your dependencies?
O3 detects CVE-2026-55982 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.