CVE-2006-6171

ProFTPD 1.3.0a and earlier does not properly set the buffer size limit when CommandBufferSize is specified in the configuration file, which leads to an off-by-two buffer underflow. NOTE: in November 2006, the role of CommandBufferSize was originally associated with CVE-2006-5815, but this was an error stemming from a vague initial disclosure. NOTE: ProFTPD developers dispute this issue, saying that the relevant memory location is overwritten by assignment before further use within the affected function, so this is not a vulnerability

Published: 2006-11-30 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2006-6171 is rated Moderate Risk (62.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.78%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2006-6171

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-24 3.86% 4.78% +0.92%
2 2025-09-16 1.16% 3.86% +2.69%
3 2025-03-30 — 1.16% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2006-6171

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2006-6171

OS Trackers for CVE-2006-6171

vendor priority summary link
alpine — CVE-2006-6171: no source package rows; 0 state rows across 0 repos (none); fixed 0, open 0. https://security.alpinelinux.org/vuln/CVE-2006-6171
debian low CVE-2006-6171 low priority: Debian including 1 source packages (proftpd-dfsg), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2006-6171
gentoo high CVE-2006-6171: 1 GLSA(s) (200611-26), 1 atom(s) (net-ftp/proftpd); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2006-6171

Affected software / configurations for CVE-2006-6171

Vendor Product Version Raw CPE
proftpd_project proftpd <= 1.3.0a cpe:2.3:a:proftpd_project:proftpd:*:*:*:*:*:*:*:*

References for CVE-2006-6171

cvelogic Threat Intelligence