CVE-2022-33108

What it actually does

Stack-based buffer overflow in Object::Copy within object.cc allows memory corruption when processing specially crafted PDF content.

Why it matters to the business

Attackers can execute arbitrary code on systems that open malicious PDFs with the affected viewer, leading to potential malware deployment, data theft, or system compromise; the vulnerability remains unpatched in listed versions with public exploit code available for over four years.

How an attack unfolds

An attacker creates a malicious PDF that triggers the Object::Copy copy routine during parsing; the victim opens the file locally with the vulnerable XPDF binary, causing the overflow to corrupt the stack and allow code execution without authentication.

How to fix it

Upgrade xpdfreader xpdf to the latest available release that resolves the stack overflow; if no fixed version exists for the deployed branch, replace the viewer with an alternative PDF reader that is actively maintained.

How to confirm the fix worked

Confirm the installed xpdf version is newer than 4.04 and test parsing of known trigger PDFs in a sandbox to verify absence of crashes or unexpected behavior.

Typical attack path

1. Craft a PDF file containing oversized or malformed object structures that exercise Object::Copy
2. Deliver the PDF via email, download link, or shared storage
3. Victim opens the file using the vulnerable xpdf binary
4. Overflow occurs during object processing, hijacking control flow for code execution

How to detect it

Review system logs and process crash dumps for xpdf segmentation faults or stack overflow signals when handling PDF files; correlate file open events with subsequent suspicious process creation or network activity.

What your security team should do

• Immediately replace or upgrade all instances of xpdfreader xpdf to a supported version
• Block or sandbox execution of xpdf on endpoints where possible
• Hunt for historical PDF files that match known malicious patterns associated with this exploit
• Add xpdf to the list of disallowed or monitored applications in endpoint policy