CVE-2026-61641 in Wallos
Summary
by MITRE • 09/01/2026
Wallos is an open-source, self-hostable personal subscription tracker. From version 4.0.0 to before version 4.9.6, Wallos's OIDC login links an incoming OIDC identity to an existing local account by matching the email claim alone, without verifying that the IdP marked that email as verified (email_verified). When Wallos is configured against an IdP that lets a user present an arbitrary or unverified email (multi-tenant IdPs, IdPs with open self-registration, or any IdP the attacker partly controls), an attacker with no Wallos account can authenticate with the admin's email and be logged in as the admin — full account takeover, no password needed. This issue has been patched in version 4.9.6.
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Analysis
by VulDB Data Team • 09/01/2026
The vulnerability identified in Wallos versions 4.0.0 through 4.9.5 represents a critical authentication bypass rooted in flawed identity provider integration logic. Specifically, the application's OpenID Connect implementation fails to validate the email_verified claim when linking an incoming OIDC identity to an existing local user account. Instead of relying on cryptographic proofs or strict attribute verification from the Identity Provider, Wallos performs a simple string match against the email address provided by the IdP. This design decision creates a significant trust boundary violation, as it assumes that any email returned by the authentication server is both authentic and owned by the presenting user. In secure identity management architectures, the presence of an unverified or arbitrarily settable email claim should not be sufficient to grant access to existing accounts, particularly administrative ones.
The operational impact of this flaw allows for complete account takeover without requiring a password or any prior knowledge of credentials. An attacker who can control or manipulate their OIDC profile on a multi-tenant identity provider, an IdP with open self-registration capabilities, or even one they partially compromise, can set their email address to match that of the Wallos administrator. Upon attempting to log in via OIDC, the application matches this fabricated email against its local database and automatically logs the attacker into the admin account. This bypasses all traditional authentication mechanisms such as passwords, two-factor authentication, or session tokens associated with legitimate users. The severity is exacerbated by the fact that it requires no prior access to the Wallos instance; a remote, unauthenticated attacker can execute this attack vector directly through standard web browser interactions.
From a classification perspective, this vulnerability aligns closely with CWE-287: Improper Authentication and CWE-613: Insufficient Session Expiration or Termination in the context of identity federation trust assumptions. It also maps to MITRE ATT&CK technique T1078: Valid Accounts, specifically within the sub-context of account manipulation via external identity providers. The core issue lies in the failure to enforce strict binding between the user's claimed identity and their actual ownership of that identity attribute as verified by a trusted source. By ignoring the email_verified flag or equivalent assertions from the IdP, Wallos treats all incoming identities with equal trust regardless of verification status, which violates fundamental principles of zero-trust architecture where no entity is trusted without explicit validation.
Mitigation strategies must focus on both immediate patching and architectural improvements to identity provider integration. The primary remediation is to upgrade Wallos to version 4.9.6 or later, where the developers have addressed this logic flaw by ensuring that only verified email claims are used for account linking. For environments unable to immediately update, administrators should restrict OIDC access to IdPs that enforce strict email verification policies and do not allow users to arbitrarily set their primary email addresses. Additionally, implementing additional checks such as requiring a pre-registered local account with explicit consent before allowing OIDC login can provide defense in depth. Organizations relying on Wallos for sensitive subscription tracking must also audit their IdP configurations to ensure that open registration or multi-tenant features are not exposed to untrusted users who could exploit this linkage mechanism.