CVE-2016-5673

UltraVNC Repeater before 1300 does not restrict destination IP addresses or TCP ports, which allows remote attackers to obtain open-proxy functionality by using a :: substring in between the IP address and port number.

Published: 2016-08-25 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-5673 is rated Moderate Risk (57.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.37%). 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-2016-5673

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 2025-03-30 1.32% 1.37% +0.06%
2 2025-03-29 1.37% 1.32% -0.06%
3 2025-03-17 — 1.37% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-5673

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N 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:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2016-5673

Affected software / configurations for CVE-2016-5673

Vendor Product Version Raw CPE
ultravnc repeater <= 1201 cpe:2.3:a:ultravnc:repeater:*:*:*:*:*:*:*:*

References for CVE-2016-5673

URL Tags
http://www.kb.cert.org/vuls/id/735416 Third Party Advisory US Government Resource
http://www.kb.cert.org/vuls/id/BLUU-A9WQVP Third Party Advisory US Government Resource
http://www.securityfocus.com/bid/92348
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