SEPTEMBER 23, 2026
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Case File

CVE-2026-8426

HIGH · CVSS 8.8 EPSS 0.17% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-05-21 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 8.8. It affects GitHub. Public exploit code or proof-of-concept references have been detected in its references. It may be remotely exploitable.

Public Exploit Signal

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

Detected Signals
remote code execution code execution

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

CVE
CVE-2026-8426
Severity
HIGH
CVSS
8.8
EPSS
0.17%
GitHub

Original NVD Description

Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/update/prepare_remote_upgrade/<remoteMPID>. An attacker who controls the remote package returned for a known marketplace item ID can overwrite the package PHP on disk and force its upgrade() method to execute in a single browser navigation. This results in remote code execution as the web server user.   In order to be vulnerable, the victim must be passing canInstallPackages, victim site must be connected to the Concrete marketplace; and the attacker controls the package returned for a marketplace item ID already installed on the victim site. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.

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