Executive brief
Emlog is an open-source website building and content management system. A security flaw in its comment module allows attackers to post malicious links that, when clicked by a site administrator or visitor, can execute unauthorized code in their browser. This could lead to the theft of login sessions, unauthorized access to the website's management area, or the redirection of users to malicious sites.
Technical details
A stored cross-site scripting (XSS) vulnerability exists in the Emlog comment module within the UBB parsing engine. The 'parseUBB' function in 'include/lib/common.php' uses a regular expression to convert '[url]' tags into HTML '<a>' tags without validating the URI scheme. By submitting a comment containing a 'javascript:' pseudo-protocol, an attacker can inject malicious scripts into the 'href' attribute. This bypasses standard HTML entity escaping because the payload resides within the attribute value. Exploitation requires a user or administrator to click the malicious link, potentially leading to session hijacking or sensitive information disclosure. The issue is fixed in version 2.6.8 by restricting URL and image tags to the http/https protocols.
Affected products
- emlog emlog < 2.6.8
Timeline
- 2026-03-27: advisory: Vendor advisory published via GitHub GHSA-74gp-xh6w-hqw6
- 2026-04-03: disclosed: CVE-2026-34229 published
- 2026-04-03: patched: Fix committed to main branch