How severe is CVE-2026-8353?

CVE-2026-8353 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-8353 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-8353?

CVE-2026-8353 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-8353?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-8353 have an EU (EUVD) identifier?

Yes. CVE-2026-8353 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31443.

When was CVE-2026-8353 published?

CVE-2026-8353 was published on 2026-05-22 and last updated on 2026-06-17.

CVE-2026-8353

CVE-2026-8353 is a medium-severity vulnerability in Concretecms Concrete Cms with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
CVSS v4: 2.1
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31443
Weakness: CWE-79
Affected product: Concretecms Concrete Cms
Published: 2026-05-22
Last modified: 2026-06-17

Description

Concrete CMS version 9.0 to 9.5.0 is vulnerable to Stored XSS via page name in the Atomik theme. A rogue editor can inject arbitrary JavaScript that executes in the context of any authenticated user visiting the affected account pages. This can lead to session hijacking, credential theft, malicious actions performed on behalf of users, and potential privilege escalation. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

Frequently asked questions

What is CVE-2026-8353?: Concrete CMS version 9.0 to 9.5.0 is vulnerable to Stored XSS via page name in the Atomik theme. A rogue editor can inject arbitrary JavaScript that executes in the context of any authenticated user visiting the affected account pages. This can lead to session hijacking, credential theft, malicious actions performed on behalf of users, and potential privilege escalation. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.
How severe is CVE-2026-8353?: CVE-2026-8353 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-8353 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-8353?: CVE-2026-8353 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-8353?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-8353 have an EU (EUVD) identifier?: Yes. CVE-2026-8353 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31443.
When was CVE-2026-8353 published?: CVE-2026-8353 was published on 2026-05-22 and last updated on 2026-06-17.

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

Affected products (1)

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

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