CVE-2026-85469: quay-builder-qemu RCE Vulnerability

CVE-2026-85469 Overview

CVE-2026-85469 is a supply chain vulnerability in quay-builder-qemu, a component used by Red Hat Quay for QEMU-based container image builds. The release workflow pins the upstream Noelware/docker-manifest-action to a mutable branch reference rather than an immutable commit hash. An attacker who compromises the upstream action can inject arbitrary code into the release pipeline. The injected code can exfiltrate registry credentials, publish malicious container images, or abuse the exposed default GITHUB_TOKEN. The weakness is classified under [CWE-1357: Reliance on Insufficiently Trustworthy Component].

Critical Impact
Successful exploitation allows attackers to steal registry credentials, publish trojanized container images, and abuse the default GitHub token to modify repository contents.

Affected Products

Red Hat quay-builder-qemu
Release workflows referencing Noelware/docker-manifest-action by mutable branch
Downstream consumers of Quay-built container images

Discovery Timeline

2026-09-16 - CVE-2026-85469 published to NVD
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-85469

Vulnerability Analysis

The vulnerability originates in the GitHub Actions release workflow for quay-builder-qemu. The workflow references the third-party Noelware/docker-manifest-action action using a mutable branch identifier instead of a full commit SHA. GitHub Actions resolves branch references at runtime, so any change to the upstream branch executes immediately in the consuming workflow.

An attacker who obtains write access to the upstream action, either through repository compromise or maintainer account takeover, can push malicious code that runs inside the Quay release pipeline. The pipeline holds registry push credentials and receives the default GITHUB_TOKEN with repository write scope. Both secrets become available to the attacker-controlled action step.

Root Cause

The root cause is the use of a mutable Git reference for a third-party GitHub Action. Pinning by branch or tag allows the referenced code to change after the workflow author reviewed it. This violates supply chain hygiene guidance that requires pinning actions by full commit SHA.

Attack Vector

Exploitation requires the attacker to first compromise the upstream Noelware/docker-manifest-action repository. Once the malicious commit lands on the referenced branch, the next quay-builder-qemu release run executes it. The malicious step can read workflow environment variables, exfiltrate registry credentials over the network, and use GITHUB_TOKEN to modify branches, releases, or workflow files. Attackers can also push tampered manifests to the container registry, poisoning downstream consumers.

No verified exploit code is publicly available. See the Red Hat CVE-2026-85469 Advisory and Red Hat Bug Report #2528219 for vendor technical details.

Detection Methods for CVE-2026-85469

Indicators of Compromise

Unexpected commits or tags in the Noelware/docker-manifest-action repository that differ from the last reviewed version.
Outbound network connections from GitHub Actions runners to unfamiliar hosts during release workflow execution.
Unrecognized container image manifests or tags published to the Quay registry outside the normal release cadence.
Unexpected use of GITHUB_TOKEN to modify workflow files, branch protections, or repository secrets.

Detection Strategies

Audit all GitHub Actions workflow files for third-party actions pinned by branch or tag and flag any not pinned by full 40-character commit SHA.
Review GitHub Actions run logs for the release workflow, focusing on steps invoking Noelware/docker-manifest-action and checking for unexpected shell commands or network calls.
Compare published container image digests against expected build outputs stored in signed provenance records.

Monitoring Recommendations

Enable GitHub Advanced Security dependency review and secret scanning across the quay-builder-qemu repository.
Forward GitHub audit logs and Actions runner telemetry to a centralized analytics platform for anomaly detection.
Monitor Quay registry push events and alert on image publications not associated with an approved release tag.

How to Mitigate CVE-2026-85469

Immediate Actions Required

Repin Noelware/docker-manifest-action in the release workflow to a specific, reviewed commit SHA rather than a branch name.
Rotate any registry credentials and personal access tokens that were exposed to the affected workflow.
Restrict the default GITHUB_TOKEN permissions to the minimum required scope using the permissions: key in the workflow YAML.
Review recent releases and registry pushes for signs of tampered artifacts.

Patch Information

Refer to the Red Hat CVE-2026-85469 Advisory for the authoritative fix status. The remediation updates the workflow to pin third-party actions by immutable commit SHA and reduces token permissions. Track Red Hat Bug Report #2528219 for progress on downstream builds.

Workarounds

Fork the upstream action into an organization-controlled repository and reference the fork by commit SHA.
Replace the third-party action with an equivalent step implemented using docker manifest commands invoked directly in the workflow.
Apply repository rulesets to require signed commits and code owner review on any workflow file changes.

bash

# Configuration example: pin action by full commit SHA and restrict token scope
permissions:
  contents: read
  packages: write

jobs:
  release:
    runs-on: ubuntu-latest
    steps:
      - name: Publish manifest
        uses: Noelware/docker-manifest-action@<REVIEWED_FULL_COMMIT_SHA>
        with:
          inputs: quay.io/example/quay-builder-qemu:latest
          images: quay.io/example/quay-builder-qemu:${{ github.sha }}
          push: true