CVE-2018-3759

private_address_check ruby gem before 0.5.0 is vulnerable to a time-of-check time-of-use (TOCTOU) race condition due to the address the socket uses not being checked. DNS entries with a TTL of 0 can trigger this case where the initial resolution is a public address but the subsequent resolution is a private address.

Published: 2018-06-13 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-3759 is rated Low Risk (32/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.69%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2018-3759

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 2026-06-15 0.18% 0.69% +0.51%
2 2025-03-17 0.08% 0.18% +0.10%
3 2023-03-07 — 0.08% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-3759

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.0 LOW
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2018-3759

GitHub Security Advisory for CVE-2018-3759

GHSA-2xvj-j3qh-x8c3 · Severity: high · Ecosystem: rubygems — private_address_check contains race condition

Affected software / configurations for CVE-2018-3759

Vendor Product Version Raw CPE
private_address_check_project private_address_check < 0.5.0 cpe:2.3:a:private_address_check_project:private_address_check:*:*:*:*:*:ruby:*:*

References for CVE-2018-3759

cvelogic Threat Intelligence