CVE-2026-79663 Ech0 before 4.7.3 Stored XSS via RSS feed tag names
Attackers with admin privileges can inject malicious scripts into RSS feed tag names, executing JavaScript in subscribers' RSS readers.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-79663?
CVE-2026-79663 is a medium-severity cross-site scripting vulnerability in lin-snow Ech0, published on 25 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-79663?
3 open source packages ship an affected version, including github.com/lin-snow/Ech0 and github.com/lin-snow/ech0.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lin-snow/Ech0 Go | All versions | 1.4.8-0.20260503035519-fd320fe3e902 |
github.com/lin-snow/Ech0 Go | All versions | 1.4.8-0.20260503035519-fd320fe3e902 |
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260503035519-fd320fe3e902 |
How do I fix CVE-2026-79663?
Upgrade github.com/lin-snow/Ech0 to 1.4.8-0.20260503035519-fd320fe3e902 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-79663 being exploited?
There is no known exploitation of CVE-2026-79663 in the wild and no public exploit code.
Sources
Also known as GHSA-3v85-fqvh-7rxf, GHSA-9277-65xq-8gww, GO-2026-5100.