CVE-2021-39847 – CVE-2021-39847 is a stack-based buffer overflow... (How to Fix)

Q: What is the severity of CVE-2021-39847?

CVE-2021-39847 has a CVSS score of 7.8 (HIGH). CVE-2021-39847 is a stack-based buffer overflow vulnerability in Adobe XMP Toolkit SDK versions 2020.1 and earlier. It allows arbitrary code execution in the context of the current user when a victim opens a specially crafted file. This affects any application or system using vulnerable versions of the XMP Toolkit SDK for metadata processing.

📋 TL;DR

CVE-2021-39847 is a stack-based buffer overflow vulnerability in Adobe XMP Toolkit SDK versions 2020.1 and earlier. It allows arbitrary code execution in the context of the current user when a victim opens a specially crafted file. This affects any application or system using vulnerable versions of the XMP Toolkit SDK for metadata processing.

💻 Affected Systems

Products:

Adobe XMP Toolkit SDK
Applications using XMP Toolkit SDK for metadata processing

Versions: 2020.1 and earlier versions

Operating Systems: Windows, Linux, macOS

Default Config Vulnerable: ⚠️ Yes

Notes: Any application that uses the vulnerable XMP SDK library to process files with XMP metadata could be affected.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

Xmp Toolkit Software Development Kit by Adobe

View all CVEs affecting Xmp Toolkit Software Development Kit →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise with attacker gaining the same privileges as the user opening the malicious file, potentially leading to data theft, ransomware deployment, or lateral movement.

🟠

Likely Case

Local privilege escalation or malware execution on the affected system, with impact limited to the user's permissions and accessible resources.

🟢

If Mitigated

No impact if proper patching and user awareness controls prevent execution of malicious files.

🌐 Internet-Facing: LOW - Exploitation requires user interaction to open a crafted file, not directly exploitable over network.

🏢 Internal Only: MEDIUM - Internal users could be targeted via phishing or malicious documents, but requires user interaction.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires user interaction (opening a crafted file) and knowledge of buffer overflow techniques. No public exploit code has been disclosed.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 2021.07 or later

Vendor Advisory: https://helpx.adobe.com/security/products/xmpcore/apsb21-65.html

Restart Required: Yes

Instructions:

1. Identify applications using XMP Toolkit SDK. 2. Update to XMP Toolkit SDK version 2021.07 or later. 3. Update any dependent applications. 4. Restart affected systems and applications.

🔧 Temporary Workarounds

Restrict file types

all

Block or restrict processing of files that could contain XMP metadata from untrusted sources

User awareness training

all

Train users not to open files from untrusted sources

🧯 If You Can't Patch

Implement application whitelisting to prevent execution of unauthorized applications
Use least privilege principles and run applications with minimal user permissions

🔍 How to Verify

Check if Vulnerable:

Check XMP Toolkit SDK version in applications or system libraries. Version 2020.1 or earlier is vulnerable.

Check Version:

Check application documentation or library files for XMP SDK version information

Verify Fix Applied:

Verify XMP Toolkit SDK version is 2021.07 or later and test with sample files containing XMP metadata.

📡 Detection & Monitoring

Log Indicators:

Application crashes when processing files with XMP metadata
Unexpected process execution following file opening

Network Indicators:

File downloads followed by application crashes

SIEM Query:

Process: (crash OR unexpected termination) AND File: (*.jpg OR *.pdf OR *.tiff OR contains XMP metadata)

📊 Metadata

CVE ID: CVE-2021-39847

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-121

Published: September 1, 2021

Last Updated: November 3, 2025

🔗 References

https://helpx.adobe.com/security/products/xmpcore/apsb21-65.html Patch,Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00032.html Mailing List,Third Party Advisory
https://helpx.adobe.com/security/products/xmpcore/apsb21-65.html Patch,Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/09/msg00032.html Mailing List,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/08/msg00003.html

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🔗 Related Vulnerabilities

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