CVE-2026-120263

Gitea OAuth2 account auto-linking takeover through the sign-up form

Published Nov 1, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
When `[oauth2_client].ACCOUNT_LINKING` is set to `auto` (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user's name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider's email or provider-derived user name; otherwise the account password is required.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
First Time appeared Gitea
Gitea gitea
Vendors & Products Gitea
Gitea gitea
Type Values Removed Values Added
Description When `[oauth2_client].ACCOUNT_LINKING` is set to `auto` (not the default) and registration is enabled, the link-account sign-up form looked up the existing account to link by the user name or email submitted in the form instead of the identity asserted by the OAuth2 provider. An attacker with an account on a configured OAuth2 provider could submit another user's name, link their external identity to that Gitea account and be signed in as it without its password, including as an administrator. The link persisted for later sign-ins. Automatic linking now only happens when the existing account matches the provider's email or provider-derived user name; otherwise the account password is required.
Title Gitea OAuth2 account auto-linking takeover through the sign-up form
Weaknesses CWE-287
CWE-639
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Gitea
Published
Updated
Nov 6, 2026, 3:43 PM
Reserved
Nov 1, 2026, 8:48 AM
Status
Deferred
Published
Nov 1, 2026, 10:18 AM
Modified
Nov 6, 2026, 4:17 PM