CVE-2020-27823

Memory corruption via incorrect encoder offsets

Published May 13, 2021 · Updated Aug 4, 2024

Out-of-bounds write in OpenJPEG before 2.4.0 allows local users to corrupt memory via crafted x,y offsets during encoding. The pngtoimage function computes image x1 and y1 by adding image offsets twice, producing incorrect bounds and a heap buffer overflow. Exploitation requires a user or process to run the encoder on attacker-controlled input; impact can include memory disclosure, data corruption, or service interruption.

CVSS severity7.8
High
EPSS probability1.11%
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 OpenJPEG before 2.4.0 allows local users to corrupt memory via crafted x,y offsets during encoding. The pngtoimage function computes image x1 and y1 by adding image offsets twice, producing incorrect bounds and a heap buffer overflow. Exploitation requires a user or process to run the encoder on attacker-controlled input; impact can include memory disclosure, data corruption, or service interruption.

The record

CVE
CVE-2020-27823
Published
May 13, 2021
Updated
Aug 4, 2024
Vendor
Université catholique de Louvain
Product
OpenJPEG
Classifications
CWE-120, CWE-787, CWE-20, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 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?

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

  1. Affected versionversion=openjpeg 2.4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Université catholique de Louvain · OpenJPEGversion=openjpeg 2.4.0

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NVDAV: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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-787Out-of-bounds Write
CWE-20Improper Input Validation
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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