CVE-2026-40036 HIGH

CVE-2026-40036: Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

Vendor Obsidianforensics
Product unfurl
Weakness CWE-770 · Uncontrolled resource consumption
Published April 8, 2026
Last update May 14, 2026
View on NVD All CVEs

CVSS base score

8.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 8, 2026 CVE published
May 14, 2026 Record updated