Uwe Ohse lrzsz up to 0.12.x lrz receive utility src/lrz.c checkpath path traversal

Summaryinfo

A vulnerability identified as critical has been detected in Uwe Ohse lrzsz up to 0.12.x. Affected by this issue is the function checkpath of the file src/lrz.c of the component lrz receive utility. This manipulation causes path traversal. This vulnerability appears as CVE-2026-105840. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Uwe Ohse lrzsz up to 0.12.x and classified as critical. Affected by this vulnerability is the function checkpath of the file src/lrz.c of the component lrz receive utility. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

lrzsz before 0.13.0 contains a path traversal vulnerability in the lrz receive utility's restricted mode that allows malicious ZMODEM senders to write files outside the current directory using absolute pathnames. Because checkpath() in src/lrz.c only rejects '../' sequences unless built with --enable-pubdir, attackers can send files named with absolute paths to overwrite any file writable by the receiving user.

It is possible to read the advisory at ohse.de. This vulnerability is known as CVE-2026-105840 since 10/06/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 366314 (Oracle Linux 8 : lrzsz (ELSA-2026-83525)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.13.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (366314) and CERT Bund (WID-SEC-2026-3978). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Red Hat Enterprise Linux
• Oracle Linux

Productinfo

Vendor

• Uwe Ohse

Name

• lrzsz

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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