Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-40036

CVE-2026-40036HIGH

obsidianforensics unfurl — Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   N   N   N   N   H    8.7   .0079   55.4     —

AFFECTED
  Product  Versions     Fixed
  unfurl   unspecified  —

TIMELINE
  Apr 8   Reserved by VulnCheck
  Apr 8   Published (CNA: VulnCheck)
  Oct 8   EXPLOIT PUBLISHED — CVE-2026-40036 (obsidianforensics unfurl). Public exploit reference added.

CWE-409, CWE-770 · CNA: VulnCheck · CVSS v4.0 · 3 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
April 8, 2026	Reserved	Reserved by VulnCheck
April 8, 2026	Published	Published (CNA: VulnCheck)
October 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-40036 (obsidianforensics unfurl). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
obsidianforensics	unfurl	—	—	—

Weaknesses

CWE-409 · CWE-770

References (3)

https://github.com/obsidianforensics/unfurl/releases/tag/v2026.04 [Release Notes]
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m [Exploit, Vendor Advisory]
https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression [Third Party Advisory]

Authoritative record: CVE-2026-40036 at cve.org

Vendors: obsidianforensics

Weaknesses: CWE-409 · CWE-770

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-40036 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.