Blocky DNSSEC validation bypass and validation-cache scope pollution

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary Blocky accepts and caches forged DNS answers while dnssec.validate: true is enabled. The issue has two related exploit paths: 1. Basic DNSSEC validation bypass. If an untrusted upstream returns an unsigned positive answer for a DNSSEC-signed public domain, Blocky classifies the response as Insecure solely because the response contains no RRSIG records. It does not first check the DS/DNSKEY chain to determine whether the queried name is below a signed delegation. The forged unsigned answer is returned and cached. 2. Validation-cache scope pollution through forged insecure proofs. If a response contains some RRSIG material and enters RRset validation, an attacker-controlled response path can still cause Blocky to cache ValidationResultInsecure for the bare domain name by returning a DS response with no DS records and an unsigned NSEC/NSEC3 record in the authority section. Blocky treats the mere presence of NSEC/NSEC3 as authenticated DS absence and stores the resulting Insecure…

Published by the source

19 Jun 2026, 20:47 UTC

Last modified by the source

19 Jun 2026, 20:47 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-x845-2f78-7v36

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# Patch Next advisory brief: GHSA-x845-2f78-7v36

Advisory: Blocky DNSSEC validation bypass and validation-cache scope pollution
IDs: GHSA-x845-2f78-7v36
Record: https://patchnext.com/advisories/ghsa-x845-2f78-7v36 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/0xERR0R/blocky 0.32.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/0xERR0R/blocky: affected >= 0.28.0, < 0.32.0; fixed in 0.32.0

## Suggested inspection (read-only)
- Go github.com/0xERR0R/blocky: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/0xERR0R/blocky.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-x845-2f78-7v36 (GitHub-reviewed advisory GHSA-x845-2f78-7v36 lists affected ranges: Go github.com/0xERR0R/blocky >=0.28.0 <0.32.0)

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