CRLF injection in basic-ftp - CVE-2026-39983
Published: April 9, 2026
Vulnerability identifier: #VU125737
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-39983
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: patrickjuchli
Affected software:
basic-ftp
basic-ftp
Detailed vulnerability description
The vulnerability allows a remote attacker to inject arbitrary FTP commands.
The vulnerability exists due to improper neutralization of CRLF sequences in high-level path APIs in dist/Client.js and FtpContext.send() when processing attacker-controlled file path parameters. A remote attacker can supply a specially crafted path containing CRLF sequences to inject arbitrary FTP commands.
The issue affects methods such as cd(), remove(), rename(), uploadFrom(), downloadTo(), list(), and removeDir().
How to mitigate CVE-2026-39983
Install security update from vendor's website.