CVE-2026-103282 in Ghost
Summary
by MITRE • 10/01/2026
Ghost versions 0.5.0 before 6.23.0 contain a concurrency issue in the staff invitation acceptance mechanism that allows multiple accounts to be created from a single invite token. Attackers can exploit this race condition by submitting concurrent requests with the same invitation token to create duplicate user accounts.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability identified within Ghost versions prior to 6.23.0 represents a critical concurrency flaw in the staff invitation acceptance mechanism, specifically categorized under CWE-362 as an improper synchronization or race condition. This security defect arises from a lack of atomic operations when processing incoming requests that utilize unique invitation tokens for account creation. In a properly secured system, once an invitation token is consumed to create a user account, it should be immediately invalidated to prevent reuse. However, in the affected versions of Ghost, the validation and consumption steps are not executed as a single indivisible transaction. This architectural oversight creates a temporal window where multiple concurrent requests carrying the same valid invitation token can pass through the initial authorization checks before any single request triggers the invalidation logic.
From an operational perspective, this race condition allows malicious actors to exploit the timing gap by submitting parallel HTTP requests simultaneously using the same invite link or token. Because the system processes these requests concurrently without adequate locking mechanisms, multiple distinct user accounts are successfully created from a single invitation intended for one individual. This behavior directly violates the principle of least privilege and integrity within identity management systems. The attacker does not need to guess credentials or bypass authentication protocols; instead, they leverage standard web request concurrency tools to flood the endpoint with identical requests, effectively multiplying their access based on a single legitimate credential grant.
The impact of this vulnerability extends beyond simple account duplication. In environments where Ghost is used for team collaboration or content management, unauthorized accounts can lead to data leakage if those accounts are granted elevated privileges such as staff or admin roles. Attackers could use these duplicated accounts to exfiltrate sensitive blog posts, access user lists, or manipulate site configurations. Furthermore, the presence of multiple identical accounts complicates audit trails and forensic analysis, making it difficult for administrators to determine which account was originally intended versus those created through exploitation. This also facilitates potential abuse of rate-limiting policies that might be tied to specific email addresses rather than unique invitation tokens, allowing attackers to bypass restrictions designed to limit repeated actions from a single source.
To mitigate this vulnerability, organizations running Ghost must upgrade immediately to version 6.23.0 or later, where the race condition has been addressed by implementing proper synchronization controls around the token consumption process. Until an upgrade is feasible, administrators should monitor for unusual spikes in account creation events associated with specific invitation tokens and consider temporarily disabling public registration if applicable. Additionally, enforcing stricter rate limiting on the user creation endpoint can help reduce the likelihood of successful concurrent exploitation attempts. From a development standpoint, this incident highlights the necessity of treating token validation and consumption as atomic operations, ensuring that once a resource is claimed by one request, it is immediately marked as unavailable to all subsequent requests within the same transactional context. This aligns with industry best practices for secure session management and identity verification outlined in standards such as OWASP Authentication Cheat Sheet and MITRE ATT&CK technique T1078 regarding valid accounts exploitation.