CVE-2026-53953: Weak RNG (CVSS 9.1)

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.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0034

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-338 CWE-338

CWE-640 CWE-640

References

Other References

https://github.com/GetSimpleCMS-CE/GetSimpleCMS-CE/security/advisories/GHSA-vvhx-56q2-gcjq https://github.com/GetSimpleCMS-CE/GetSimpleCMS-CE/security/advisories/GHSA-vvhx-56q2-gcjq

Frequently Asked Questions

What is CVE-2026-53953? +

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-53953? +

CVE-2026-53953 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0034, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53953? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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