CVE-2020-27824Public exploit

Encoder crash via unchecked decomposition levels

Published May 13, 2021 · Updated Aug 4, 2024

Out-of-bounds read in OpenJPEG before 2.4.0 allows local users to crash the encoder through excessive decomposition levels. opj_dwt_calc_explicit_stepsizes indexes the fixed-size opj_dwt_norms_real table directly with an excessive level instead of using the bounds-aware accessor. Triggering requires an encoding operation with crafted decomposition settings, and the demonstrated consequence is encoder process termination.

CVSS severity5.5
Medium
EPSS probability1.61%
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 read in OpenJPEG before 2.4.0 allows local users to crash the encoder through excessive decomposition levels. opj_dwt_calc_explicit_stepsizes indexes the fixed-size opj_dwt_norms_real table directly with an excessive level instead of using the bounds-aware accessor. Triggering requires an encoding operation with crafted decomposition settings, and the demonstrated consequence is encoder process termination.

The record

CVE
CVE-2020-27824
Published
May 13, 2021
Updated
Aug 4, 2024
Vendor
Université catholique de Louvain
Product
OpenJPEG
Classifications
CWE-125, CWE-20, T1499.004
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

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 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-125Out-of-bounds Read
CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

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Technologies

Your stack

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Your stack

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