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TI-2021-18807 Aliases CVE-2021-42521GHSA-xfhg-9pjg-xg7g

Uncontrolled resource consumption in vtk

Priority LOW 36CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-400.

Summary

There is a NULL pointer dereference vulnerability in VTK before 9.2.5, and it lies in IO/Infovis/vtkXMLTreeReader.cxx. The vendor didn't check the return value of libxml2 API 'xmlDocGetRootElement', and try to dereference it. It is unsafe as the return value can be NULL and that NULL pointer dereference may crash the application.

Why it matters now

EPSS 0.01316 70th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed vtk (PyPI): 9.0.1

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—vtkVTK - 9.0.0 and before—No fix listedCNA
—vtk (PyPI)before 9.0.19.0.1Patch availableGHSA-xfhg-9pjg-xg7g
  • vtk Vendor— Affected VTK - 9.0.0 and before Fixed in — No fix listed CNA
  • vtk (PyPI) Vendor— Affected before 9.0.1 Fixed in 9.0.1 Patch available GHSA-xfhg-9pjg-xg7g

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vtk:vtk:*:*:*:*:*:*:*:*up to 9.0.0Vulnerablevtk
  • cpe:2.3:a:vtk:vtk:*:*:*:*:*:*:*:* Versions up to 9.0.0 Vulnerable ·vtk

Remediation

  • Fix · GHSA-xfhg-9pjg-xg7g vtk (PyPI) Fixed in 9.0.1 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-42521
  2. 2026-10-03 Alias added: GHSA-xfhg-9pjg-xg7g

References

Exploit 1

Advisory 2

Other 4

  • TI-2025-35446 Kitware VTK (Visualization Toolkit) through 9.5.0 contains a heap use-after-free… CVSS 3.1CRITICAL 9.8
  • TI-2025-35445 Kitware VTK (Visualization Toolkit) through 9.5.0 contains a heap buffer overflow… CVSS 3.1HIGH 7.1
  • TI-2025-35444 Kitware VTK (Visualization Toolkit) up to 9.5.0 is vulnerable to Buffer Overflow in… CVSS 3.1HIGH 7.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences