Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

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

Medium 4.8

In plain English

A medium-severity cross-site scripting in Ech0 from lin-snow. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.8Medium

Exploit odds (30 days)0.3%top 83.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/lin-snow/Ech0	1.4.8-0.20260503035519-fd320fe3e902	GHSA-3v85-fqvh-7rxf
Go	github.com/lin-snow/ech0	1.4.8-0.20260503035519-fd320fe3e902	GO-2026-5100

Affected products (as reported)

Vendor	Product	Versions
lin-snow	Ech0	0 – before 4.7.3

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

References

GitHub Security Advisory (GHSA-3v85-fqvh-7rxf) vendor-advisory
VulnCheck Advisory: Ech0 before 4.7.3 Stored XSS via RSS feed tag names third-party-advisory