Sigstore-js: Registry credential disclosure (CVE-2026-118763)

The sigstore-js library, specifically the RegistryClient.uploadBlob() method, contains a vulnerability where it fails to constrain the destination of requests to an OCI registry's specified upload location. An attacker who controls or compromises an OCI registry can return a malicious blob-upload URL. When the library attempts to upload an artifact, it sends a PUT request to the attacker's host, including credentials (bearer tokens, Basic auth, or custom headers) originally intended for the legitimate registry. This vulnerability is a residual issue from CVE-2026-59891, where previous fixes were insufficient to scope credentials to the registry origin. Version 0.7.2 addresses this by isolating credentials and enforcing origin matching.

Impact

Successful exploitation allows for the theft of sensitive authentication credentials, including bearer tokens and Basic credentials used for registry access.

Recommendation

• Upgrade sigstore-js to version 0.7.2 or later immediately.
• Review registry interaction logs for instances where attachArtifactToImage() requests result in redirects or cross-origin POST/PUT operations to non-registry domains.
• If using sigstore-js within CI/CD pipelines, ensure the registry host configuration follows the principle of least privilege and verify that CI secrets are scoped to specific registry endpoints.