CVE-2026-40036

EUVD-2026-20779
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.
Data Amplification
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 43%
Affected Products (NVD)
VendorProductVersion
ryandfirunfurl
𝑥
< 2026.04
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m
https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression