CVE-2020-27823 – This vulnerability in OpenJPEG's encoder allows... (How to Fix)

Q: What is the severity of CVE-2020-27823?

CVE-2020-27823 has a CVSS score of 7.8 (HIGH). This vulnerability in OpenJPEG's encoder allows attackers to pass specially crafted x,y offset input during encoding, potentially leading to memory corruption. It affects systems using vulnerable versions of OpenJPEG for image processing. The flaw can compromise confidentiality, integrity, and system availability.

📋 TL;DR

This vulnerability in OpenJPEG's encoder allows attackers to pass specially crafted x,y offset input during encoding, potentially leading to memory corruption. It affects systems using vulnerable versions of OpenJPEG for image processing. The flaw can compromise confidentiality, integrity, and system availability.

💻 Affected Systems

Products:

OpenJPEG

Versions: Versions before 2.4.0

Operating Systems: Linux, Windows, macOS

Default Config Vulnerable: ⚠️ Yes

Notes: Affects any application using OpenJPEG library for JPEG2000 image encoding.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, and persistent backdoor installation.

🟠

Likely Case

Application crash (denial of service) or limited memory corruption allowing information disclosure.

🟢

If Mitigated

Application crash with no data loss if proper sandboxing and privilege separation are implemented.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: LOW

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires crafting malicious JPEG2000 images and triggering encoding.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: OpenJPEG 2.4.0 and later

Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=1905762

Restart Required: Yes

Instructions:

1. Update OpenJPEG to version 2.4.0 or later. 2. Restart affected services. 3. Rebuild applications linked against OpenJPEG.

🔧 Temporary Workarounds

Disable JPEG2000 processing

all

Prevent processing of JPEG2000 images in affected applications.

# Application-specific configuration required

🧯 If You Can't Patch

Implement strict input validation for image files
Run OpenJPEG in sandboxed/containerized environment with minimal privileges

🔍 How to Verify

Check if Vulnerable:

Check OpenJPEG version: opj_decompress -v 2>&1 | grep version

Check Version:

opj_decompress -v 2>&1 | grep version

Verify Fix Applied:

Confirm version is 2.4.0 or later: opj_decompress -v 2>&1 | grep -E 'version.*2\.4|version.*2\.[5-9]|version.*[3-9]'

📡 Detection & Monitoring

Log Indicators:

Application crashes with OpenJPEG error messages
Segmentation faults in image processing services

Network Indicators:

Unusual JPEG2000 file uploads to web applications
Image processing API calls with malformed parameters

SIEM Query:

source="application.log" AND ("OpenJPEG" OR "JPEG2000") AND ("crash" OR "segfault" OR "memory corruption")

📊 Metadata

CVE ID: CVE-2020-27823

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-20

Published: May 13, 2021

Last Updated: November 21, 2024

🔗 References

https://bugzilla.redhat.com/show_bug.cgi?id=1905762 Issue Tracking,Patch,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00011.html Mailing List,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQR4EWRFFZQDMFPZKFZ6I3USLMW6TKTP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJUPGIZE6A4O52EBOF75MCXJOL6MUCRV/
https://www.debian.org/security/2021/dsa-4882 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1905762 Issue Tracking,Patch,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/02/msg00011.html Mailing List,Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQR4EWRFFZQDMFPZKFZ6I3USLMW6TKTP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WJUPGIZE6A4O52EBOF75MCXJOL6MUCRV/
https://www.debian.org/security/2021/dsa-4882 Third Party Advisory

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