CVE-2026-104025

Published Oct 15, 2026 Modified Oct 15, 2026 CWE-22 CWE-693

Description

Path Traversal (CWE-22) in the execute_obj function of the archive object viewer (peach.pas) in PeaZip 11.2.0 and earlier on Windows allows an attacker who convinces a victim to preview an entry of a crafted archive via the "Preview with... -> Associated application" action (Shift+Ctrl+O) to execute an arbitrary program already present on the victim's system, with no warning dialog. The function validates only outname (PeaZip's own temporary directory) with checkfiledirname, while the string actually executed is the concatenation outname+tempstring; tempstring is taken verbatim from the archive entry name (StringGridList.Cells[12,...]) and is never validated. checkfiledirname (list_utils.pas) rejects control and reserved characters in the file name but performs no ".." path-containment check, so an entry named ../../../../Windows/System32/calc.exe escapes the extraction directory and is passed to cp_open -> ShellExecuteW; the extracting backend (7-Zip) strips the traversal while the opener does not. In addition, the SECEXTCONST dangerous-extension confirmation prompt is implemented only in the double-click handler (grid_obj_open) and not on this preview route, so an executable inside an archive reaches ShellExecuteW unannounced, and where the prompt does fire it names the entry's display name rather than the resolved path that will run. Arbitrary code execution was demonstrated with a proof of concept against official PeaZip builds, confirmed on two archive formats (.zip and .tar) to show the defect is in PeaZip's own path handling and not in a single format parser.

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Weakness Type (CWE)

CWE-22 Path Traversal
CWE-693 CWE-693

References

Frequently Asked Questions

What is CVE-2026-104025? +
Path Traversal (CWE-22) in the execute_obj function of the archive object viewer (peach.pas) in PeaZip 11.2.0 and earlier on Windows allows an attacker who convinces a victim to preview an entry of a crafted archive via the "Preview with... -> Associated application" action (Shift+Ctrl+O) to execute an arbitrary program already present on the victim's system, with no warning dialog. The function validates only outname (PeaZip's own temporary directory) with checkfiledirname, while the string actually executed is the concatenation outname+tempstring; tempstring is taken verbatim from the archive entry name (StringGridList.Cells[12,...]) and is never validated. checkfiledirname (list_utils.pas) rejects control and reserved characters in the file name but performs no ".." path-containment check, so an entry named ../../../../Windows/System32/calc.exe escapes the extraction directory and is passed to cp_open -> ShellExecuteW; the extracting backend (7-Zip) strips the traversal while the opener does not. In addition, the SECEXTCONST dangerous-extension confirmation prompt is implemented only in the double-click handler (grid_obj_open) and not on this preview route, so an executable inside an archive reaches ShellExecuteW unannounced, and where the prompt does fire it names the entry's display name rather than the resolved path that will run. Arbitrary code execution was demonstrated with a proof of concept against official PeaZip builds, confirmed on two archive formats (.zip and .tar) to show the defect is in PeaZip's own path handling and not in a single format parser.
How do I check if I'm vulnerable to CVE-2026-104025? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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