CVE-2026-40036: Ryandfir Unfurl

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

Unfurl before 2026.04 contains an unbounded zlib decompression vulnerability in parse_compressed.py that allows remote attackers to cause denial of service. Attackers can submit highly compressed payloads via URL parameters to the /json/visjs endpoint that expand to gigabytes, exhausting server memory and crashing the service.

Affected products

• Ryandfir Unfurl: before 2026.04 (fixed in 2026.04)

Published 2026-04-08. Last modified 2026-10-08.