CWE-201
AllowedInsertion of Sensitive Information Into Sent Data
Abstraction: Base · Status: Draft
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
741 vulnerabilities reference this CWE, most recent first.
GHSA-XXPM-5C34-X4C3
Vulnerability from github – Published: 2026-08-04 21:30 – Updated: 2026-08-05 21:31Google::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.
{
"affected": [],
"aliases": [
"CVE-2026-66901"
],
"database_specific": {
"cwe_ids": [
"CWE-201"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-04T21:16:37Z",
"severity": "HIGH"
},
"details": "Google::Auth versions before 0.09 for Perl allow server side request forgery and credential exfiltration via unvalidated URLs taken from the credentials JSON.\n\nThe 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.\n\nAny caller that builds credentials from a configuration it does not fully control issues those requests from the application\u0027s 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.\n\nVersion 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.",
"id": "GHSA-xxpm-5c34-x4c3",
"modified": "2026-08-05T21:31:35Z",
"published": "2026-08-04T21:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66901"
},
{
"type": "WEB",
"url": "https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/9b5157062acc605ca9e6c507b910587f4829ce9e.patch"
},
{
"type": "WEB",
"url": "https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/c95c77e70bec94f17e239d88050f843ea1cade95.patch"
},
{
"type": "WEB",
"url": "https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/cbbb07804e3f8cc7cf9638ecc9c2097d80a9ef50.patch"
},
{
"type": "WEB",
"url": "https://github.com/GoogleCloudPlatform/google-auth-library-perl/commit/cd42bdef53afcc4531161e85e91d0d5997e01324.patch"
},
{
"type": "WEB",
"url": "https://metacpan.org/release/CJCOLLIER/Google-Auth-0.09/changes"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/08/04/34"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation
Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
Mitigation
Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere. Any information that is not necessary to the functionality should be removed in order to lower both the overhead and the possibility of security sensitive data being sent.
Mitigation
Setup default error messages so that unexpected errors do not disclose sensitive information.
Mitigation MIT-46
Strategy: Separation of Privilege
- Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
CAPEC-12: Choosing Message Identifier
This pattern of attack is defined by the selection of messages distributed via multicast or public information channels that are intended for another client by determining the parameter value assigned to that client. This attack allows the adversary to gain access to potentially privileged information, and to possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could be used to change the adversary's identifier to more a privileged one.
CAPEC-217: Exploiting Incorrectly Configured SSL/TLS
An adversary takes advantage of incorrectly configured SSL/TLS communications that enables access to data intended to be encrypted. The adversary may also use this type of attack to inject commands or other traffic into the encrypted stream to cause compromise of either the client or server.
CAPEC-612: WiFi MAC Address Tracking
In this attack scenario, the attacker passively listens for WiFi messages and logs the associated Media Access Control (MAC) addresses. These addresses are intended to be unique to each wireless device (although they can be configured and changed by software). Once the attacker is able to associate a MAC address with a particular user or set of users (for example, when attending a public event), the attacker can then scan for that MAC address to track that user in the future.
CAPEC-613: WiFi SSID Tracking
In this attack scenario, the attacker passively listens for WiFi management frame messages containing the Service Set Identifier (SSID) for the WiFi network. These messages are frequently transmitted by WiFi access points (e.g., the retransmission device) as well as by clients that are accessing the network (e.g., the handset/mobile device). Once the attacker is able to associate an SSID with a particular user or set of users (for example, when attending a public event), the attacker can then scan for this SSID to track that user in the future.
CAPEC-618: Cellular Broadcast Message Request
In this attack scenario, the attacker uses knowledge of the target’s mobile phone number (i.e., the number associated with the SIM used in the retransmission device) to cause the cellular network to send broadcast messages to alert the mobile device. Since the network knows which cell tower the target’s mobile device is attached to, the broadcast messages are only sent in the Location Area Code (LAC) where the target is currently located. By triggering the cellular broadcast message and then listening for the presence or absence of that message, an attacker could verify that the target is in (or not in) a given location.
CAPEC-619: Signal Strength Tracking
In this attack scenario, the attacker passively monitors the signal strength of the target’s cellular RF signal or WiFi RF signal and uses the strength of the signal (with directional antennas and/or from multiple listening points at once) to identify the source location of the signal. Obtaining the signal of the target can be accomplished through multiple techniques such as through Cellular Broadcast Message Request or through the use of IMSI Tracking or WiFi MAC Address Tracking.
CAPEC-621: Analysis of Packet Timing and Sizes
An attacker may intercept and log encrypted transmissions for the purpose of analyzing metadata such as packet timing and sizes. Although the actual data may be encrypted, this metadata may reveal valuable information to an attacker. Note that this attack is applicable to VOIP data as well as application data, especially for interactive apps that require precise timing and low-latency (e.g. thin-clients).
CAPEC-622: Electromagnetic Side-Channel Attack
In this attack scenario, the attacker passively monitors electromagnetic emanations that are produced by the targeted electronic device as an unintentional side-effect of its processing. From these emanations, the attacker derives information about the data that is being processed (e.g. the attacker can recover cryptographic keys by monitoring emanations associated with cryptographic processing). This style of attack requires proximal access to the device, however attacks have been demonstrated at public conferences that work at distances of up to 10-15 feet. There have not been any significant studies to determine the maximum practical distance for such attacks. Since the attack is passive, it is nearly impossible to detect and the targeted device will continue to operate as normal after a successful attack.
CAPEC-623: Compromising Emanations Attack
Compromising Emanations (CE) are defined as unintentional signals which an attacker may intercept and analyze to disclose the information processed by the targeted equipment. Commercial mobile devices and retransmission devices have displays, buttons, microchips, and radios that emit mechanical emissions in the form of sound or vibrations. Capturing these emissions can help an adversary understand what the device is doing.