Inefficient regular expression complexity in basic-ftp - #VU146762
Published: September 2, 2026
Vulnerability identifier: #VU146762
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-1333
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in the Unix directory-listing parser in Client.list() when parsing a server-supplied directory listing. A remote attacker can return a specially crafted directory listing line to cause a denial of service.
A normal line placed last can cause the Unix parser to be selected, while an earlier crafted line triggers quadratic-time backtracking and can freeze the Node.js event loop.
Affected software
basic-ftp
Remediation
Install security update from vendor's website.
basic-ftp - update to 6.2.1