XSS in Lin-Snow Ech0
CVE-2026-79663
Ech0 before 4.7.3 contains a stored cross-site scripting vulnerability in the public RSS feed where tag names and markdown content are rendered without HTML escaping. Attackers with admin privileges can inject malicious tag names or raw HTML in echo content that executes as JavaScript in RSS readers that render HTML-type summaries, affecting anonymous subscribers and other users.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (15.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.3% 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: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/lin-snow/Ech0/security/advisories/GHSA-3v85-fqvh-7rxf (vendor-advisory)
- www.vulncheck.com/advisories/ech0-before-stored-xss-via-rss-feed-tag-names (third-party-advisory)
Frequently asked questions
- What is CVE-2026-79663?
- CVE-2026-79663 is a medium-severity vulnerability in Lin-Snow Ech0, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-08-25.
- How severe is CVE-2026-79663?
- Medium severity. CVSS v3 base score is 4.8 out of 10.