CVE-2021-36080Network attack vector

Process crash via aliased handle-stream double free

Published Jul 1, 2021 · Updated Aug 4, 2024

Heap double-free in GNU LibreDWG 0.12.3.4163 through 0.12.3.4191 allows attackers to crash an encoding process via crafted DWG data. When a handle overflow such as num_reactors causes hdl_dat to share dat's chain, encoder cleanup calls bit_chain_free on the aliased allocation twice. Exploitation requires an application to encode attacker-supplied DWG content; the observed consequence is a heap-error crash.

CVSS severity8.8
High
EPSS probability1.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap double-free in GNU LibreDWG 0.12.3.4163 through 0.12.3.4191 allows attackers to crash an encoding process via crafted DWG data. When a handle overflow such as num_reactors causes hdl_dat to share dat's chain, encoder cleanup calls bit_chain_free on the aliased allocation twice. Exploitation requires an application to encode attacker-supplied DWG content; the observed consequence is a heap-error crash.

The record

CVE
CVE-2021-36080
Published
Jul 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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

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-415Double Free

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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