Is CVE-2026-34558 in the CISA KEV catalog?

No. CVE-2026-34558 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34558?

CVE-2026-34558 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2026-34558?

CVE-2026-34558 has an EPSS score of 0.31% (22th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-34558

CRITICAL

9.1

CVSS v3

NVD

Description

CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.0.0, the application fails to properly sanitize user-controlled input within the Methods Management functionality when creating or managing application methods/pages. Multiple input fields accept attacker-controlled JavaScript payloads that are stored server-side without sanitization or output encoding. These stored values are later rendered directly into administrative interfaces and global navigation components without proper encoding, resulting in Stored DOM-Based Cross-Site Scripting (XSS). This issue has been patched in version 0.31.0.0.

CWE-79Cross-Site Scripting (XSS)

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

Exploit Intelligence

0.31%probability of exploitation in 30 days

22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-v77r-xg3p-75g7

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-06.