CVE-2020-21426Public exploit

Code execution via unchecked EXR read length

Published Aug 22, 2023 · Updated Oct 4, 2024

Heap buffer overflow in FreeImage 3.18.0 allows remote attackers to execute code or crash an application via a crafted EXR image. PluginEXR.cpp's C_IStream::read forwards an EXR-derived byte count to read_proc without verifying that the destination buffer is large enough. The target application must process the image; successful corruption compromises that application's process, while the demonstrated outcome is an abort.

CVSS severity7.8
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in FreeImage 3.18.0 allows remote attackers to execute code or crash an application via a crafted EXR image. PluginEXR.cpp's C_IStream::read forwards an EXR-derived byte count to read_proc without verifying that the destination buffer is large enough. The target application must process the image; successful corruption compromises that application's process, while the demonstrated outcome is an abort.

The record

CVE
CVE-2020-21426
Published
Aug 22, 2023
Updated
Oct 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1204.002User Execution Malicious File
T1203Exploitation for Client Execution

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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