CVE-2026-40036Proof of concept (PoC) published · CISASuited to automated attack · CISA

Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression

CVSS score

8.7

EPSS probability

%0.8

Risk score

0.1

Published

6 mo ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-40036 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

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.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-40036 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	obsidianforensics	unfurl	View
2	ryandfir	unfurl	View

Total affected vendors: 2|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
8.7	CVSS V4_0	HIGH	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	CVE CNA
8.7	CVSS V40	HIGH	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD
7.5	CVSS V3_1	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CVE CNA
7.5	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

VulnCheck Advisory: dfir-unfurl - Denial of Service via Unbounded zlib Decompression

Open source

reference

VulnCheck Advisory: dfir-unfurl - Denial of Service via Unbounded zlib Decompression

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-40036 is associated with the following CWEs:

CWE-770: Allocation of Resources Without Limits or Throttling CWE-409: Common Weakness Enumeration Entry CWE-409

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-40036 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

GHSA Advisory GHSA-h5qv-qjv4-pc5mvendor-advisory VulnCheck Advisory: dfir-unfurl - Denial of Service via Unbounded zlib Decompressionpatch https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompressionvendor-advisory

CVSS Vector Radar Chart

8.7 / 10

Vulnerability Scoring Details

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)High

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

obsidianforensics

ryandfir

Weakness Type (CWE & CAPEC)

CWE-770 CWE-409

Similar Vulnerabilities

9.3

CVE-2026-40035

Unfurl - Werkzeug Debugger Exposure via String Config Parsing

VendorobsidianforensicsProductunfurl+2 etkilenen

Patch status unknownEPSS %16 mo ago

Get this vulnerability through the API

Affected products, version ranges, exploitation status and patch information in a single request, with a free key.

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curl -H "x-api-key: $DAYBREACH_API_KEY" \
  "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-40036"