GHSA-c3f2-qg8v-25q2: Duplicate Advisory Denial of Service Vulnerability

HIGH
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CVSS 7.5
CWE-409
Published
Advisory Summary

GHSA-c3f2-qg8v-25q2 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)) affecting Duplicate Advisory libraries in the PyPI ecosystem. The issue involves unfurl's unbounded zlib decompression allows decompression bomb dos. Remediation is available by upgrading affected packages to version 2026.04.

GHSA-c3f2-qg8v-25q2 at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-c3f2-qg8v-25q2
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
Affected Product Duplicate Advisory
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix GHSA-c3f2-qg8v-25q2

To remediate this vulnerability, upgrade all affected Duplicate Advisory dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

dfir-unfurl fixed: 2026.04 
pip install dfir-unfurl>=2026.04
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show dfir-unfurl

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-c3f2-qg8v-25q2, inspect your installed packages using pip:

pip show dfir-unfurl

Analyze the terminal output to locate any version of Duplicate Advisory in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2026.04), your application is affected.

Note: The pip show dfir-unfurl command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-409: Improper Handling of Highly Compressed Data (Data Amplification), where the product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. In Duplicate Advisory, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-h5qv-qjv4-pc5m. This link is maintained to preserve external references. ### Original 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.

GHSA-c3f2-qg8v-25q2 Affected Duplicate Advisory Versions

1 component(s)
Fixed Versions:
2026.04
Product / Package Ecosystem Affected Versions Fixed Version
dfir-unfurl
pypi/dfir-unfurl
PyPI
< 2026.04
2026.04

References

GitHub Advisory / Wiki ADVISORY
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m
NVD — GHSA-c3f2-qg8v-25q2 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40036
Duplicate Advisory Source Repository REPOSITORY
https://github.com/RyanDFIR/unfurl/pull/243
Duplicate Advisory Source Repository REPOSITORY
https://github.com/RyanDFIR/unfurl
Duplicate Advisory Release RELEASE
https://github.com/RyanDFIR/unfurl/releases/tag/v2026.04
www.vulncheck.com/advisories/dfir-unf... WEB
https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression

Frequently Asked Questions

What is GHSA-c3f2-qg8v-25q2?
GHSA-c3f2-qg8v-25q2 is a security vulnerability in Duplicate Advisory involving Unfurl's unbounded zlib decompression allows decompression bomb DoS under CWE-409: Improper Handling of Highly Compressed Data (Data Amplification).
Which Duplicate Advisory versions are affected?
Affected versions include releases prior to 2026.04 across affected packages: dfir-unfurl.
What version fixes GHSA-c3f2-qg8v-25q2?
Upgrading to 2026.04 (or the latest patched release for your respective branch) resolves the vulnerability.
Is dfir-unfurl affected?
Yes, dfir-unfurl is affected in releases prior to 2026.04. Upgrade your dependency to 2026.04 or later.
What is the CVSS score of GHSA-c3f2-qg8v-25q2?
GHSA-c3f2-qg8v-25q2 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with GHSA-c3f2-qg8v-25q2?
GHSA-c3f2-qg8v-25q2 is classified under CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) (The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.).
How can I check PyPI dependencies for GHSA-c3f2-qg8v-25q2?
Run the dependency tree command: 'pip show dfir-unfurl'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-c3f2-qg8v-25q2",
  "modified" : "2026-04-10T17:18:31Z",
  "published" : "2026-04-09T00:31:59Z",
  "withdrawn" : "2026-04-10T17:18:31Z",
  "aliases" : [ ],
  "summary" : "Duplicate Advisory: Unfurl's unbounded zlib decompression allows decompression bomb DoS",
  "details" : "### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-h5qv-qjv4-pc5m. This link is maintained to preserve external references.\n\n### Original Description\nUnfurl 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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "dfir-unfurl"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2026.04"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40036"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/RyanDFIR/unfurl/pull/243"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/RyanDFIR/unfurl"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/RyanDFIR/unfurl/releases/tag/v2026.04"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-409" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-10T17:18:31Z",
    "nvd_published_at" : "2026-04-08T22:16:24Z"
  }
}