CVE-2021-40145Network attack vector

Service crash via GD2 encoder double free

Published Aug 26, 2021 · Updated Aug 4, 2024

Double-free flaw in LibGD through 2.3.2 allows attackers to trigger a service crash via crafted GD2 image data. The gdImageGd2Ptr path in gd_gd2.c mishandles cleanup while producing GD2 output, releasing allocated memory twice when an error path is reached. The CVE is disputed by the vendor, and exploitation requires a component that processes attacker-influenced GD2 data; reported impact is denial of service without stated confidentiality or integrity loss.

CVSS severity7.5
High
EPSS probability2.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free flaw in LibGD through 2.3.2 allows attackers to trigger a service crash via crafted GD2 image data. The gdImageGd2Ptr path in gd_gd2.c mishandles cleanup while producing GD2 output, releasing allocated memory twice when an error path is reached. The CVE is disputed by the vendor, and exploitation requires a component that processes attacker-influenced GD2 data; reported impact is denial of service without stated confidentiality or integrity loss.

The record

CVE
CVE-2021-40145
Published
Aug 26, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 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

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

Weakness, pattern, technique

CWE-415Double Free
T1499Endpoint Denial of Service

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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