Is This vulnerability exploited in the wild?

No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

How severe is This vulnerability?

Medium severity, with a CVSS score of 5.9, published 7 July 2026.

Which products and versions are affected?

github.com/tinfoil-factory/netfoil (Go) < 0.3.0; Tinfoil Factory Netfoil < 0.3.0.

Is there a fix for This vulnerability?

A patch was published on 0.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is This vulnerability attacked?

It is attacked with local access, in a software library.

Check whether you run github.com/tinfoil-factory/netfoil (Go) or Tinfoil Factory Netfoil at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

tinfoil-factory netfoil domain name filter bypass via multiple questions

Q: Is there a fix for This vulnerability?

A patch was published on 0.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is This vulnerability attacked?

It is attacked with local access, in a software library.

Q: Am I affected?

Check whether you run github.com/tinfoil-factory/netfoil (Go) or Tinfoil Factory Netfoil at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Severity: medium · CVSS 5.9 · Published 2026-07-07

netfoil is a Go-based library used for handling network traffic and DNS filtering. A security flaw allows a local attacker to bypass domain name filters by including multiple questions in a single DNS request. This could allow unauthorized access to restricted websites or services that the software was intended to block.

Technologies: github.com/tinfoil-factory/netfoil (Go), Tinfoil Factory Netfoil. Vendors: Go, Tinfoil Factory.

Quick answers

Is This vulnerability exploited in the wild?: No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
How severe is This vulnerability?: Medium severity, with a CVSS score of 5.9, published 7 July 2026.
Which products and versions are affected?: github.com/tinfoil-factory/netfoil (Go) < 0.3.0; Tinfoil Factory Netfoil < 0.3.0.
Is there a fix for This vulnerability?: A patch was published on 0.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?: It is attacked with local access, in a software library.
Am I affected?: Check whether you run github.com/tinfoil-factory/netfoil (Go) or Tinfoil Factory Netfoil at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability exists in netfoil versions prior to 0.3.0 where the domain name filter can be bypassed due to an interpretation conflict (CWE-436). When a DNS request contains multiple questions, the filter may only validate the first (legitimate) question while allowing subsequent restricted domains to pass through to a remote DNS-over-HTTPS (DoH) server. This requires a local attacker to be able to craft multi-question DNS packets and for the upstream DoH server to support such requests. The issue is resolved in version 0.3.0.

Affected products

tinfoil-factory netfoil < 0.3.0

Timeline

2026-05-31: disclosed
2026-07-07: advisory
0.3.0: patched

References

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