CVE-2020-27844Public exploit

Heap corruption via unchecked PLT buffer subtraction

Published Jan 5, 2021 · Updated Aug 4, 2024

Heap-based buffer overflow in OpenJPEG before 2.4.0 allows context-dependent attackers to corrupt memory through crafted encoding input. opj_j2k_write_sod subtracts reserved PLT bytes from the remaining output-buffer length after relying on a debug-only assertion, so opj_t2_encode_packet performs an out-of-bounds copy. Triggering requires conversion or encoding of untrusted input with crafted progression-order parameters; reading an image alone does not reach the flaw, and the process can crash or suffer memory corruption.

CVSS severity7.8
High
EPSS probability1.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap-based buffer overflow in OpenJPEG before 2.4.0 allows context-dependent attackers to corrupt memory through crafted encoding input. opj_j2k_write_sod subtracts reserved PLT bytes from the remaining output-buffer length after relying on a debug-only assertion, so opj_t2_encode_packet performs an out-of-bounds copy. Triggering requires conversion or encoding of untrusted input with crafted progression-order parameters; reading an image alone does not reach the flaw, and the process can crash or suffer memory corruption.

The record

CVE
CVE-2020-27844
Published
Jan 5, 2021
Updated
Aug 4, 2024
Vendor
Université catholique de Louvain
Product
OpenJPEG
Classifications
CWE-20, T1203
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 5, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 privilegesUnavailable in this record.

What is affected?

Université catholique de Louvain · OpenJPEGversion=openjpeg 2.4.0

Published CVSS scores

8.3NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:C
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.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo