CVE-2026-101023 in Gitea
Summary
by MITRE • 10/07/2026
Gitea's OAuth2 token endpoint verified the signature and grant of a token submitted with the `refresh_token` grant type, but not that the token was a refresh token. An unexpired access token for the same OAuth2 application and grant could be exchanged for a new access token and refresh token. Whoever holds such an access token could keep access beyond the token's original lifetime.
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified in Gitea represents a critical flaw within its implementation of the OpenID Connect and OAuth 2.0 authentication flows, specifically concerning the handling of token refresh operations. The core technical deficiency lies in the validation logic applied to requests submitted with the refresh_token grant type. While the system correctly verifies the cryptographic signature and the validity period of the provided credential, it fails to enforce a strict classification check on the token itself. This oversight allows an attacker possessing any valid access token for the same OAuth2 application to submit that token as if it were a refresh token at the designated endpoint. Because the server does not distinguish between short-lived access tokens and long-lived refresh tokens during this specific exchange process, it accepts the input and issues new credentials in response.
This logic error effectively bypasses the intended expiration mechanism for access tokens. In standard OAuth 2.0 implementations, access tokens are designed to have a limited lifespan to minimize the window of opportunity for misuse if they are compromised. Refresh tokens, conversely, are issued with longer lifespans and specific scopes to allow clients to obtain new access tokens without requiring user re-authentication. By allowing an access token to be exchanged for a fresh pair of access and refresh tokens, Gitea inadvertently grants the holder of that access token the ability to perpetually extend their session validity. This transforms a temporary compromise into a persistent unauthorized access scenario, as the attacker can continuously cycle through new credentials without triggering additional authentication challenges or alerts related to token expiration.
The operational impact of this vulnerability is severe for any organization relying on Gitea for source code management and collaboration. An adversary who obtains an access token, whether through phishing, session hijacking, or exposure in logs, can maintain indefinite control over the associated account. This persistence undermines the principle of least privilege by allowing prolonged unauthorized actions such as pushing malicious code, exfiltrating sensitive repository data, or modifying project settings. Furthermore, because the new tokens are issued with valid signatures and appear legitimate to downstream services, detection through standard monitoring tools may be delayed until significant damage has occurred. The ability to rotate credentials seamlessly also complicates incident response efforts, as revoking a single token does not terminate the attacker's access if they have already obtained subsequent refreshed tokens.
From a classification perspective, this flaw aligns with CWE-287, which denotes Improper Authentication, specifically regarding the failure to verify the type of credential presented during authentication exchanges. It also relates to CWE-613, Insufficient Session Expiration, as the vulnerability allows sessions to persist far beyond their intended duration without proper re-validation. In terms of adversary tactics, this behavior facilitates the ATT&CK technique T1528, Steal Application Access Token, by enabling the continuous harvesting and renewal of valid tokens from a single initial compromise point. The lack of strict token type validation represents a fundamental deviation from RFC 6749 standards for OAuth 2.0 authorization frameworks.
To mitigate this vulnerability, immediate patching to the latest version of Gitea is required as it contains the corrected logic that strictly validates whether the submitted credential is indeed a refresh token before processing the exchange request. Administrators should also audit their OAuth2 application configurations to ensure that client applications are adhering to best practices by storing and using only appropriate token types for specific operations. Implementing additional monitoring for unusual patterns of token renewal requests can help detect potential exploitation attempts in real-time. Furthermore, organizations should consider implementing short-lived access tokens with automatic rotation mechanisms where supported, reducing the value of any single stolen credential while ensuring that refresh token handling remains strictly isolated from general authentication endpoints to prevent such logic bypasses.