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Fencer Intel
high 7.5

CVE-2021-42521 json

VTK NULL pointer dereference vulnerability

published 4y ago modified 4mo ago also GHSA-xfhg-9pjg-xg7g , PYSEC-2022-255 , EUVD-2022-0352

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

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.

Patch / fix

  • pypi vtk 9.0.1
  • vtk9 Debian 14, Debian 13 9.1.0+really9.1.0+dfsg2-8

debian advisories DEBIAN-CVE-2021-42521

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-42521 updated cvss 7.5

vtk: NULL pointer dereference vulnerability

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.32% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • gitlab.kitware.com https://gitlab.kitware.com/vtk/vtk/issues/17818 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi vtk
<9.0.1
9.0.1

Affected products

  • n/a vtk

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-476 NULL Pointer Dereference

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.