SB20261110263 - Inefficient regular expression complexity in basic-ftp

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Main Vulnerability Database SB20261110263

SB20261110263 - Inefficient regular expression complexity in basic-ftp

Published: November 10, 2026

Security Bulletin ID SB20261110263
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Partial DoS

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Inefficient regular expression complexity (CVE-ID: N/A)

CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a temporary denial of service by blocking a basic-ftp client's Node.js event loop.

The vulnerability exists due to quadratic-time regular-expression backtracking in MLSD listing detection and PASV response parsing when processing crafted FTP server responses. A remote attacker can operate or compromise an FTP server and return a listing line of repeated '=' characters without ';', or refuse EPSV and return a PASV '227 ' response containing a long comma-free digit sequence, to stall all work sharing the client's event loop.


Remediation

Install update from vendor's website.

References