CVE-2026-40036

HIGH

Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

Title source: cna
STIX 2.1

Description

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.

References (3)

Core 3
Core References
Vendor Advisory vendor-advisory
GHSA Advisory GHSA-h5qv-qjv4-pc5m
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m
Patch release-notes patch
VulnCheck Advisory: dfir-unfurl - Denial of Service via Unbounded zlib Decompression
https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04

Scores

CVSS v3 7.5
EPSS 0.0051
EPSS Percentile 39.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-409 CWE-770
Status published
Products (3)
obsidianforensics/unfurl < 2026.04
pypi/dfir-unfurl 0 - 20260405PyPI
ryandfir/unfurl < 2026.04
Published Apr 08, 2026
Tracked Since Apr 09, 2026