CVE-2026-40036

HIGH

Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

Title source: cna

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)

[Vendor Advisory] https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m

[Patch] https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04

[Third Party Advisory] https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression

Scores

CVSS v3 7.5

EPSS 0.0014

EPSS Percentile 34.0%

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