CVE-2020-23559

Access violation via invalid DCR parser write

Published Sep 16, 2022 · Updated Aug 4, 2024

Out-of-bounds write in IrfanView 4.54 allows local users to trigger an access violation by supplying a crafted DCR image. The 32-bit FORMATS.dll DCR parser reaches ShowPlugInSaveOptions_W and writes a word through an invalid computed address. Exploitation requires the crafted file to be opened in IrfanView; published evidence demonstrates a user-mode access violation, not code execution.

CVSS severity7.8
High
EPSS probability0.33%
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 IrfanView 4.54 allows local users to trigger an access violation by supplying a crafted DCR image. The 32-bit FORMATS.dll DCR parser reaches ShowPlugInSaveOptions_W and writes a word through an invalid computed address. Exploitation requires the crafted file to be opened in IrfanView; published evidence demonstrates a user-mode access violation, not code execution.

The record

CVE
CVE-2020-23559
Published
Sep 16, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1204.002
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2022CVE 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 vectorlocal
Required privilegesUnavailable in this record.

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:L/UI:N/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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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