CVE-2026-66901

HighCVSS 7.5

Published: 04/08/2026(UTC)Updated: 26/08/2026(UTC)Translated: 05/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.35%

27th percentile - higher than 27% of all known CVEs

Summary

Vulnerability in Google::Auth for Perl before version 0.09 allows SSRF and credential exfiltration. URLs taken from the credentials JSON are not validated against the universe domain, enabling requests to internal services and link-local endpoints with application credentials.

Risk Assessment

The organization risks exposure of sensitive data (tokens, secrets) and access to internal network resources if the application uses unvalidated credential configuration files.

Recommendation

Immediately upgrade Google::Auth to version 0.09 or later and ensure all credential configuration files come from trusted sources.

Other vulnerabilities in Google::Auth

CVE-2026-66902Critical
Google::Auth for Perl before version 0.06 runs a command named in an external_account credentials JSON via an ungated system call. The Pluggable subclass reads credential_source.executable.command and runs it as `system($command)`, passing the whole string to /bin/sh -c. No opt-in gate guards the call, and the path is reached from the standard Application Default Credentials flow.

Original NVD description (English source)

Google::Auth versions before 0.09 for Perl allow server side request forgery and credential exfiltration via unvalidated URLs taken from the credentials JSON. The URLs the library requests are read from the credentials JSON, and their hosts were not checked against the universe domain before the request. For an external_account configuration, retrieve_subject_token fetched credential_source.url with headers from the same JSON, and fetch_access_token posted the subject token to token_url, then sent the STS access token it received to service_account_impersonation_url in an Authorization: Bearer header. The authorized_user, impersonated_service_account and service_account configurations posted the client secret and refresh token, the source access token, and a signed JWT assertion to their own JSON-supplied token_uri or impersonation URL. Any caller that builds credentials from a configuration it does not fully control issues those requests from the application's network position, reaching hosts the configuration names, including internal services and link-local metadata endpoints, and hands them the credentials each request carries. The service_account assertion is bound to aud, so it is not replayable against Google. Version 0.06 added a _validate_url host check to the external_account class, keyed on a universe_domain read from the same credentials JSON. Version 0.07 gated a JSON-supplied universe domain behind GOOGLE_EXTERNAL_ACCOUNT_ALLOW_CUSTOM_UNIVERSES=1, deriving the pin flag from arguments that an earlier BUILDARGS pass had already merged on the make_creds path. Version 0.08 passed the pin decision through as an explicit constructor argument and moved _validate_url to Google::Auth::Credentials, adding the call to UserRefreshCredentials and ImpersonatedServiceAccountCredentials, and 0.09 added it to ServiceAccountCredentials.