CVE-2021-28236Public exploitNetwork attack vector

Process crash via unchecked binary DXF pointers

Published Dec 2, 2021 · Updated Aug 3, 2024

NULL pointer dereference in GNU LibreDWG 0.12.3 allows attackers to crash dwg2dxf by converting crafted DWG input to binary DXF. The dxfb_tables_write function dereferences absent table objects at four sites after malformed DWG data leaves expected pointers NULL. The file must reach the binary DXF output path; the demonstrated consequence is termination of the converting process.

CVSS severity7.5
High
EPSS probability1.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in GNU LibreDWG 0.12.3 allows attackers to crash dwg2dxf by converting crafted DWG input to binary DXF. The dxfb_tables_write function dereferences absent table objects at four sites after malformed DWG data leaves expected pointers NULL. The file must reach the binary DXF output path; the demonstrated consequence is termination of the converting process.

The record

CVE
CVE-2021-28236
Published
Dec 2, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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