Description

GetSimple CMS is a content management system (CMS), and GetSimple CMS CE is the community edition of that CMS. In version 3.3.22, the password reset endpoint can be accessed without authentication. When a reset request is submitted for an existing user, the application generates a new temporary password and immediately stores its hash as the user's new password. The temporary password is generated using PHP rand() seeded with microtime(). Because this seed is time-based and has a limited effective search space, an attacker can generate possible reset password candidates. Since the admin login endpoint does not enforce rate limiting or account lockout, these candidates can be tested online until the correct password is found. Successful exploitation may lead to administrator account takeover. At time of publication, there are no publicly available patches.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.1",
  "pubDate": "2026-10-01T20:17:25.283Z",
  "pubdate": "2026-10-01T20:17:25.283Z",
  "executiveSummary": "GetSimple CMS and GetSimple CMS CE version 3.3.22 contain a critical vulnerability in the password reset mechanism, classified as an insecure randomness flaw.\nThe vulnerability allows an unauthenticated remote attacker to compromise user accounts, including administrator accounts, by predicting the temporary passwords generated during the reset process.\nThe root cause is the reliance on the PHP rand() function seeded with microtime(), which provides insufficient entropy for security-sensitive operations.\nBecause the application lacks rate limiting or account lockout mechanisms on the login endpoint, an attacker can brute-force the predicted password space efficiently.\nThe impact includes full administrative account takeover, potentially leading to complete system compromise, unauthorized data access, and further malicious activities within the CMS environment.\nThe risk is high due to the lack of available patches at the time of discovery, necessitating immediate defensive configuration changes to protect existing deployments.",
  "technicalDetails": "The vulnerability resides in the password reset functionality of GetSimple CMS 3.3.22, where the application fails to utilize cryptographically secure pseudo-random number generators (CSPRNG).\nWhen a user triggers a password reset, the system invokes PHP rand() to generate a temporary credential. This function is seeded using microtime(), a predictable value based on the server's current timestamp at the moment of execution.\nThe attack flow begins with the attacker submitting a password reset request for a target administrative account via the unauthenticated endpoint. Upon submission, the server generates the temporary password hash based on the deterministic seed.\nBecause the entropy of the microtime() seed is limited and the generation algorithm is public, an attacker can reconstruct the state of the random number generator if the approximate time of the request is known. This significantly reduces the search space for the temporary password.\nThe exploitation process involves the attacker calculating a list of candidate passwords generated by the system within a specific window of time corresponding to the request. Since the application does not enforce rate limiting or account lockout, the attacker can programmatically iterate through these candidate passwords against the login endpoint.\nOnce the correct candidate is matched, the attacker successfully authenticates as the administrator, resulting in full control over the CMS instance.\nThe vulnerable component is the password reset logic, which lacks robust validation or delayed processing. The absence of defensive measures against automated login attempts further facilitates the successful brute-forcing of the predicted credentials.\nThis vulnerability is exacerbated by the lack of account lockout or MFA (Multi-Factor Authentication) implementation, which would otherwise serve as a barrier to the brute-force phase of the exploit chain."
}