# netfoil: Incorrect block responses could lead to localhost traffic Advisory record · `GHSA-xvg2-cgv6-6h7v` - **Identifiers:** `GHSA-xvg2-cgv6-6h7v` · `GO-2026-6143` - **State:** Confirmed - **Severity:** CVSS 4.0, no score published - **Critical:** No - **Weakness (CWE):** [CWE-693](https://cwe.mitre.org/data/definitions/693.html) - **Tags:** [CWE-693](https://agentprime.io/advisories/tag/cwe-693.md) - **Published:** 29 Jul 2026 - **Updated:** 18 Aug 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 29 Jul 2026, 17:03 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `github.com/tinfoil-factory/netfoil` (Go): affected `<0.4.0`; fixed in `0.4.0` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > netfoil, a Go package, is vulnerable in versions before 0.4.0. Blocked DNS queries received a 0.0.0.0 answer instead of NXDOMAIN, so on Linux the traffic meant for a blocked destination was sent to localhost rather than dropped. The impact depends on which services are running locally and on firewall rules; the source gives few other details. Upgrade to version 0.4.0 or later. Written 6 Nov 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - Score not published, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`, from GitHub Advisory Database - **CISA KEV:** Not listed. - **EPSS:** No score. ## Timeline - 31 Oct 2026, 14:50 UTC: First seen by agentprime - 31 Oct 2026, 14:50 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-xvg2-cgv6-6h7v) ## Sources - [GitHub Advisory Database: GHSA-xvg2-cgv6-6h7v](https://github.com/advisories/GHSA-xvg2-cgv6-6h7v) - [OSV: GHSA-xvg2-cgv6-6h7v](https://osv.dev/vulnerability/GHSA-xvg2-cgv6-6h7v) - - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .