CVE-2026-105840: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in Uwe Ohse lrzsz
Description
CVE-2026-105840 is a path traversal vulnerability in the lrzsz utility before version 0.13.0. It affects the lrz receive utility's restricted mode, allowing malicious ZMODEM senders to write files outside the intended directory by using absolute pathnames. The vulnerability arises because the pathname check only rejects '../' sequences unless compiled with a specific option, enabling attackers to overwrite any file writable by the receiving user.
CVSS v4.0
Score 7.7high
Affected software
Uwe Ohse
lrzsz
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in lrzsz prior to 0.13.0 involves improper limitation of pathnames in the lrz receive utility's restricted mode. The function checkpath() in src/lrz.c does not reject absolute pathnames, only '../' sequences unless built with --enable-pubdir. This allows attackers sending files via ZMODEM protocol to specify absolute paths and overwrite arbitrary files writable by the user running the utility.
Potential Impact
An attacker can overwrite arbitrary files on the system with the privileges of the user running the lrz receive utility. This can lead to data corruption, privilege escalation, or system compromise depending on the files overwritten. The vulnerability requires user interaction (sending files) and network access to the service.
Mitigation Recommendations
A fix is available in lrzsz version 0.13.0. Users should upgrade to version 0.13.0 or later to remediate this vulnerability. No vendor advisory content was provided to indicate alternative mitigations or temporary fixes.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-10-05T22:00:10.842Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ac4fc542cdf04f656b4d68e
Added to database: 10/06/2026, 13:49:08 UTC
Last enriched: 10/06/2026, 14:04:12 UTC
Last updated: 10/06/2026, 18:57:28 UTC
Views: 11
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