CVE-2026-79663: Ech0 before 4.7.3 Stored XSS via RSS feed tag names

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-25 · updated 2026-08-31
Weakness: CWE-79

Description

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.

Affected products

lin-snow Ech0: before 4.7.3 — fixed in 4.7.3

How to fix

Upgrade to a fixed version: lin-snow Ech0 4.7.3. Check the vendor advisory for mitigations.

References

https://github.com/lin-snow/Ech0/security/advisories/GHSA-3v85-fqvh-7rxf
https://www.vulncheck.com/advisories/ech0-before-stored-xss-via-rss-feed-tag-names

Get alerted when CVE-2026-79663 or the next vulnerability affects your stack