CVE-2026-66901
Google::Auth versions before 0.09 for Perl allow server side request forgery and credential exfiltration via unvalidated URLs taken from the credentials JSON
Description
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.
INFO
Published Date :
Aug. 4, 2026, 9:16 p.m.
Last Modified :
Aug. 4, 2026, 11:16 p.m.
Remotely Exploit :
No
Source :
9b29abf9-4ab0-4765-b253-1875cd9b441e
Affected Products
The following products are affected by CVE-2026-66901
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update Google::Auth to version 0.09 or later.
- Validate all external URLs.
- Restrict access to sensitive endpoints.
- Implement strict host validation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-66901.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-66901 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-66901
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-66901 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-66901 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Aug. 04, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/08/04/34 -
New CVE Received by 9b29abf9-4ab0-4765-b253-1875cd9b441e
Aug. 04, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/GoogleCloudPlatform/google-auth-library-perl', 'vendor': 'CJCOLLIER', 'product': 'Google::Auth', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.09', 'versionType': 'custom'}], 'packageName': 'Google-Auth', 'programFiles': ['lib/Google/Auth/ExternalAccountCredentials.pm', 'lib/Google/Auth/ServiceAccountCredentials.pm', 'lib/Google/Auth/UserRefreshCredentials.pm', 'lib/Google/Auth/ImpersonatedServiceAccountCredentials.pm'], 'collectionURL': 'https://cpan.org/modules', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'Google::Auth::ExternalAccountCredentials::retrieve_subject_token'}, {'name': 'Google::Auth::ExternalAccountCredentials::fetch_access_token'}, {'name': 'Google::Auth::ServiceAccountCredentials::fetch_access_token'}, {'name': 'Google::Auth::UserRefreshCredentials::fetch_access_token'}, {'name': 'Google::Auth::ImpersonatedServiceAccountCredentials::fetch_access_token'}]}] Added Description 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. Added CWE CWE-918 Added CWE CWE-201 Added Reference https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/9b5157062acc605ca9e6c507b910587f4829ce9e.patch Added Reference https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/c95c77e70bec94f17e239d88050f843ea1cade95.patch Added Reference https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/cbbb07804e3f8cc7cf9638ecc9c2097d80a9ef50.patch Added Reference https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/cd42bdef53afcc4531161e85e91d0d5997e01324.patch Added Reference https://metacpan.org/release/CJCOLLIER/Google-Auth-0.09/changes