CVE-2021-21898Network attack vector

Code execution via unchecked decompression literal length

Published Nov 19, 2021 · Updated Aug 3, 2024

Out-of-bounds write in LibreCAD libdxfrw 2.2.0-rc2-19-ge02f3580 allows attackers to execute code via a crafted DWG file. The dwgCompressor::decompress18 routine trusts a file-controlled literal count and copies that many bytes into a heap buffer without checking its allocated size. Opening an attacker-supplied AC1018 or AC1024 DWG file is required; the overwrite permits code execution or a process crash.

CVSS severity8.8
High
EPSS probability2.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in LibreCAD libdxfrw 2.2.0-rc2-19-ge02f3580 allows attackers to execute code via a crafted DWG file. The dwgCompressor::decompress18 routine trusts a file-controlled literal count and copies that many bytes into a heap buffer without checking its allocated size. Opening an attacker-supplied AC1018 or AC1024 DWG file is required; the overwrite permits code execution or a process crash.

The record

CVE
CVE-2021-21898
Published
Nov 19, 2021
Updated
Aug 3, 2024
Vendor
LibreCAD
Product
libdxfrw
Classifications
CWE-119, CWE-787, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=LibreCad libdxfrw 2.2.0-rc2-19-ge02f3580

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LibreCAD · libdxfrwversion=LibreCad libdxfrw 2.2.0-rc2-19-ge02f3580

Published CVSS scores

8.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
T1204.002User Execution: Malicious File

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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