CVE-2026-63203
Deferred Deferred - Pending Action

Logto Account API Token Exposure via Missing Scope Validation

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: GitHub, Inc.

Description
Logto is the modern, open-source auth infrastructure for SaaS and AI apps. From 1.31.0 until 1.42.0, the Account API handlers in packages/core/src/routes/account/third-party-tokens.ts allow a caller holding a same-user access token with only the openid scope to retrieve stored social or enterprise SSO provider access tokens through GET /api/my-account/identities/{target}/access-token or GET /api/my-account/sso-identities/{connectorId}/access-token. The handlers authenticate the user but do not require the identities scope that protects neighboring identity-detail operations, bypassing the intended Account API consent boundary. Exploitation requires federated token-set storage to be enabled and the affected user to have authenticated through a supported connector. A low-trust application can use the disclosed provider token against upstream APIs within that token's granted scopes. This issue is fixed in version 1.42.0.

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-25
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-63203
EUVD
EUVD-2026-86223

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
logto logto From 1.31.0 (inc) to 1.41.0 (inc)
logto logto 1.42.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

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Executive Summary

This vulnerability affects Logto versions 1.31.0 to 1.42.0. It allows an attacker with a low-privilege access token (only openid scope) to retrieve stored social or enterprise SSO provider access tokens via specific Account API endpoints. The issue bypasses intended consent boundaries because these endpoints do not enforce the identities scope required by other identity-related operations.

Detection Guidance

To detect this vulnerability, check if your Logto instance is running a vulnerable version (1.31.0 to 1.41.0). Verify if the affected endpoints (GET /api/my-account/identities/{target}/access-token, GET /api/my-account/sso-identities/{connectorId}/access-token) return tokens without requiring the identities scope. Use tools like curl to test these endpoints with an openid-scoped token and check for unauthorized token retrieval.

Impact Analysis

An attacker could use the disclosed provider tokens to access upstream APIs within the token's granted scopes. This could lead to unauthorized actions on behalf of the affected user, such as accessing sensitive data or performing privileged operations. Exploitation requires federated token storage to be enabled and the user to have authenticated via a supported connector.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive user data, potentially violating GDPR's data protection principles and HIPAA's safeguards for protected health information. Unauthorized token access may result in data breaches, non-compliance with consent requirements, and failure to maintain adequate security controls.

Mitigation Strategies

Immediately upgrade Logto to version 1.42.0 or later to apply the fix. Ensure the identities scope is enforced on all relevant endpoints. Review access logs for suspicious requests to the affected endpoints. Disable federated token-set storage if not required.

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