XSS in Shaarli
CVE-2026-48822
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a stored Cross-Site Scripting (XSS) vulnerability in the Markdown-to-HTML conversion process used in the Bookmark Description field. An authenticated user can inject a malicious javascript: URI inside a Markdown link. The vulnerability originates in the filterProtocols method within BookmarkMarkdownFormatter.php.This method attempts to sanitize Markdown links by filtering dangerous protocols (such as javascript:) before rendering. It uses the following regular expression: (#]\((.*?)\)#is). This regex is designed to detect inline Markdown links, but it fails to detect Markdown reference-style links because reference-style links are resolved by the Markdown parser after preprocessing. The filterProtocols method never inspects the actual URL used in these references and as a result, an attacker can supply a javascript: URI inside a reference definition. This issue has been fixed in version 0.16.2.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (5.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 5.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Shaarli — versions < 0.16.2
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-48822?
- CVE-2026-48822 is a medium-severity vulnerability in Shaarli, classified under Cross-site Scripting. CVSS score: 5.8/10. Published 2026-06-17.
- How severe is CVE-2026-48822?
- Medium severity. CVSS v3 base score is 5.8 out of 10.