Is CVE-2026-30940 in the CISA KEV catalog?

No. CVE-2026-30940 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-30940?

CVE-2026-30940 has a CVSS v3 base score of 7.2 (HIGH).

What is the EPSS score for CVE-2026-30940?

CVE-2026-30940 has an EPSS score of 1.05% (60th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-30940?

Upgrade basercms to 5.2.3 or later.

CVE & CISA-KEV Catalog

CVE-2026-30940

HIGH

7.2

CVSS v3

NVD

Description

baserCMS is a website development framework. Prior to version 5.2.3, a path traversal vulnerability exists in the theme file management API (/baser/api/admin/bc-theme-file/theme_files/add.json) that allows arbitrary file write. An authenticated administrator can include ../ sequences in the path parameter to create a PHP file in an arbitrary directory outside the theme directory, which may result in remote code execution (RCE). This issue has been patched in version 5.2.3.

CWE-22Path Traversal CWE-73External Control of File Name or Path

How to fix

Remediation Available

basercmsNVD

Affected:< 5.2.3Fixed in:5.2.3CVE-2026-30940derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

1.05%probability of exploitation in 30 days

60thpercentile

Moderate risk: more likely to be exploited than 60% of all known CVEs.

References

Exploit1

github.com

Vendor Advisory1

basercms.net

Release Notes1

github.com

Related Vulnerabilities

Other CWE-22 (Path Traversal) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-23897	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-32315	High	8.6	100%	KEV	Fix
CVE-2022-29464	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-26086	Medium	5.3	100%	KEV	Fix
CVE-2021-22005	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-5902	Critical	9.8	100%	KEV + Ransom	Fix

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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 2026-04-01.