🛡️ CVE-2026-8434 — concrete-cms

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

• Attack vector: Network — reachable from anywhere that can route to the service.
• Attack complexity: Low — the attack works reliably, with no preparation.
• Privileges required: None — an unauthenticated stranger can try it.
• User interaction: Required — someone has to click, open or visit something.
• Scope: Unchanged — the damage stays inside the vulnerable component.
• Confidentiality impact: High — total loss, or loss the attacker controls.
• Integrity impact: High — total loss, or loss the attacker controls.
• Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-8434 is classified as CWE-352: Cross-Site Request Forgery (CSRF). A state-changing request is accepted without proof it was intended, so another site can trigger it using the victim's session.

Affected software

CVE-2026-8434 is recorded against 2 packages.

• concrete-cms (from 9.0.0 up to 9.5.1)
• concrete5/concrete5 (from 9.0.0RC1 up to 9.5.1)

Timeline and source

Published on 21 May 2026 and last revised on 23 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

documentation.concretecms.org

Other advisories for this package

concrete-cms has other advisories on record. If you are patching this one, these are worth checking on the same host:

• CVE-2026-8353 (4.8 Medium, published 22 May 2026)
• CVE-2026-8347 (4.3 Medium, published 22 May 2026)
• CVE-2026-8340 (4.3 Medium, published 22 May 2026)
• CVE-2026-8411 (8.8 High, published 21 May 2026)
• CVE-2026-8237 (5.3 Medium, published 21 May 2026)
• CVE-2026-7882 (4.3 Medium, published 21 May 2026)
• CVE-2026-8417 (8.8 High, published 21 May 2026)
• CVE-2026-8337 (5.3 Medium, published 21 May 2026)

Same weakness in other software

These advisories are the same class of weakness (CWE-352: Cross-Site Request Forgery (CSRF)) in other software:

• CVE-2023-37465 (published 27 Jul 2026)
• CVE-2023-6022 (8.0 High, published 7 Jul 2026)
• CVE-2022-43719 (8.0 High, published 7 Jul 2026)
• CVE-2016-4808 (published 6 Jul 2026)
• CVE-2021-4164 (8.0 High, published 2 Jul 2026)
• CVE-2011-4952 (8.0 High, published 2 Jul 2026)
• CVE-2022-44630 (4.6 Medium, published 11 Jun 2026)
• CVE-2022-47150 (4.3 Medium, published 11 Jun 2026)

Details

Affected Packages

References