Vulnerability · Published Aug 3, 2026 · Assigned by VulnCheck

CVE-2026-67617Microweber CMS 2.0.20 Stored XSS via tag_names Parameter

Medium 4.8

In plain English

A medium-severity cross-site scripting in microweber from microweber. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).

Severity (CVSS 3.1)4.8Medium

Exploit odds (30 days)0.3%top 80.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Microweber CMS through 2.0.20 contains a stored cross-site scripting vulnerability in the content tagging system that allows admin-authenticated attackers to inject arbitrary JavaScript by submitting malicious payloads via the tag_names parameter of the GET /api/save_content_admin endpoint, bypassing three independent sanitization controls including XSS middleware that ignores GET requests, a strip_unsafe() function that only matches double-quoted onerror attributes, and a titlecase normalizer that passes HTML decimal entity-encoded payloads through unchanged. Attackers can store malicious scripts that execute without user interaction for every visitor to the public blog page and within the admin post editor, enabling session riding through same-origin fetch requests using the CSRF token embedded in the page.

Affected products (as reported)

Vendor	Product	Versions
microweber	microweber	0 – through 2.0.20

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

References

Researcher Disclosure technical-description, exploit
https://www.vulncheck.com/advisories/microweber-cms-stored-xss-via-tag-names-parameter third-party-advisory