CVE-2020-21831Network attack vector

Service crash via heap overflow in DWG parser

Published May 17, 2021 · Updated Jul 9, 2026

Heap-based buffer overflow in GNU LibreDWG 0.10 allows remote attackers to cause service interruption via a crafted DWG file. The read_2004_section_handles routine decodes R2004 section handles without sufficient bounds validation, permitting writes beyond an allocated heap buffer during malformed-file parsing. The condition requires a user or service to process attacker-supplied DWG content; published evidence demonstrates crashes, while code execution is not established.

CVSS severity8.8
High
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in GNU LibreDWG 0.10 allows remote attackers to cause service interruption via a crafted DWG file. The read_2004_section_handles routine decodes R2004 section handles without sufficient bounds validation, permitting writes beyond an allocated heap buffer during malformed-file parsing. The condition requires a user or service to process attacker-supplied DWG content; published evidence demonstrates crashes, while code execution is not established.

The record

CVE
CVE-2020-21831
Published
May 17, 2021
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-122, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record 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

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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