Security readout for executives and security teams
Plain-English summary
This flaw can let a Ruby application believe it is connecting to a public address while the actual socket reaches a private address. It matters when the gem is used to block internal-network access, such as in URL fetching or SSRF defenses.
Executive priority
Prioritize remediation if this gem protects outbound requests exposed to users or third parties. Otherwise, handle in normal dependency maintenance, while confirming version status because the source bundle has limited severity data.
Technical view
The private_address_check Ruby gem has a TOCTOU race: the address validated during DNS resolution may differ from the address used by the socket. The CVE describes TTL 0 DNS changing from a public address to a private address between check and use.
Likely exposure
Exposure is likely limited to Ruby applications using private_address_check to validate outbound network destinations. Risk is highest where untrusted users can influence hostnames or URLs and the application relies on this gem to prevent private-address connections.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not listed as KEV. The described condition requires DNS behavior that changes answers between validation and connection, using TTL 0 to trigger the race.
Researcher notes
The bundle has no CVSS score and inconsistent version wording: the title and description say before 0.5.0, while the affected entry lists 0.5.0. Treat vendor metadata as the authority before closing findings.
Mitigation direction
- Inventory Ruby applications using the private_address_check gem.
- Verify installed versions against vendor guidance and the referenced fix commit.
- Upgrade away from versions described as vulnerable before 0.5.0.
- Review outbound request controls that rely on DNS-based private address checks.
- Add defense-in-depth egress restrictions for internal address ranges.
Validation and detection
- Check dependency lockfiles for private_address_check usage and version.
- Confirm whether the application accepts user-controlled hostnames or URLs.
- Review code paths where the gem gates outbound socket creation.
- Test that private-address blocking applies to the connected socket address.
- Document any compensating network egress controls.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-362: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2018-3759 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/jtdowney/private_address_check/commit/4068228187db87fea7577f7020099399772bb147CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.