Security Update: Hollo 0.6.19 Released

We have released Hollo 0.6.19 to address a security vulnerability in Fedify's HTML parsing code.

This vulnerability (CVE-2025-68475) is a ReDoS (Regular Expression Denial of Service) issue that could allow an attacker to cause service unavailability by sending specially crafted HTML responses during federation operations. The malicious payload is small (approximately 170 bytes) but can block the Node.js event loop for extended periods.

We strongly recommend all Hollo operators upgrade to version 0.6.19 immediately.

#Hollo #Security #Fediverse #ActivityPub