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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Ryandfir Unfurl
cpe:2.3:a:ryandfir:unfurl:*:*:*:*:*:*:*:*
|
— |
2026.04
|
References 3
https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04
disclosure@vulncheck.com
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-…
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounde…
disclosure@vulncheck.com