CVE-2026-102990

basic-ftp: Quadratic-time CPU denial of service in Client.list() Unix directory-listing parser (RE_LINE backtracking)

HIGH
8.2
CVSS Score
Published: September 30, 2026 at 07:44 PM UTC
Updated: September 30, 2026 at 09:17 PM UTC
1 product affected across 1 vendorBasic FTP

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Severity
HIGH8.2
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

basic-ftp is an FTP client for Node.js. Prior to 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.2.1
Affected range stops below 6.2.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-1333

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