CVE-2026-40036

high

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

Advisories
More

https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression

https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m

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

Details

Source: Mitre, NVD

Published: 2026-04-08

Updated: 2026-04-17

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 8.7

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

Severity: High

EPSS

EPSS: 0.00099