CVE-2026-40036 PUBLISHED

Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

Assigner: VulnCheck
Reserved: 08.04.2026 Published: 08.04.2026 Updated: 08.04.2026

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.

CVSS 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
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	obsidianforensics
Product	unfurl
Versions	Default: unaffected affected from 0 to 2026.04 (excl.)

CVE-2026-40036 PUBLISHED

Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

Metrics

Product Status

Credits

References

Problem Types