CVE-2026-8435

Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion()

2.3 LowFix available

Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion(). The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Passive

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.11%Up 0.1 points since May 22, 2026

What each source reports

CVE List Score used 2.3

Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion()

Record: CVE-2026-8435
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-352, CWE-1275
Updated: 2026-11-02

EUVDEUVD-2026-31363 2.3

Record: EUVD-2026-31363
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-44q4-354f-c826 2.3

Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion()

Concrete CMS 9 through 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion().

Record: GHSA-44q4-354f-c826
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness: CWE-352
Updated: 2026-11-02

NVD 2.3

Record: CVE-2026-8435
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness: CWE-352, CWE-1275
Updated: 2026-11-02

OSV 2.3

Concrete CMS 9 before 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion()

Record: CVE-2026-8435
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-1275, CWE-352
Updated: 2026-11-02

OSVGHSA-44q4-354f-c826 2.3

Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion()

Concrete CMS 9 through 9.5.0 is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion().

Record: GHSA-44q4-354f-c826
CVSS 4.0: 2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness: CWE-352
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`concrete5/concrete5` Packagist	9.0.0RC1 up to 9.5.1	9.5.1
`concrete5/concrete5` Packagist	9.0.0RC1 up to 9.5.1, plus listed versions 9.0.09.0.0RC39.0.0RC49.0.19.0.2 Show 39 moreShow less 9.1.09.1.19.1.29.1.39.2.09.2.0RC29.2.19.2.29.2.39.2.49.2.59.2.69.2.79.2.89.2.99.3.09.3.19.3.29.3.39.3.49.3.59.3.69.3.79.3.89.3.99.4.09.4.0RC19.4.0RC29.4.19.4.29.4.39.4.49.4.59.4.69.4.79.4.89.5.09.5.0RC19.5.0RC2	9.5.1

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-8435 is a low vulnerability (CVSS 2.3) in Concrete Cms Cms, published May 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.11%, the 1st percentile. Fixed in concrete5/concrete5 9.5.1.