SEPTEMBER 14, 2026
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Case File

CVE-2026-81905

MEDIUM · CVSS 6.3 EPSS 0.21% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

Concrete CMS versions prior to 9.5.3 are vulnerable due to improper handling of user validation hashes, allowing an attacker to misuse hashes intended for one purpose (e.g., registration) to exploit another (e.g., password reset). This flaw requires an attacker to first acquire a valid hash through methods such as email interception, which amplifies the risk associated with hash disclosure. Organizations using affected versions should prioritize remediation to mitigate potential account takeover risks.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-81905
Severity
MEDIUM
CVSS
6.3
EPSS
0.21%

Original NVD Description

Concrete CMS below 9.5.3 stores user validation hashes for multiple purposes (email/registration validation, password reset, and persistent login) in a single table with a type column, but the redemption path resolves a hash by value alone and does not verify its type. As a result, a hash issued for one purpose can be redeemed for another: a long-lived registration hash (60-day expiry) can be submitted to the password-change endpoint to set a new password on the target account, and a password-reset hash can be submitted to the email-validation endpoint to activate an account. Exploitation requires the attacker to first obtain a valid hash through a separate channel (for example email interception, log exposure, or SSRF against an internal mail relay), so the flaw amplifies the impact of any hash disclosure rather than creating a standalone entry point. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.