What’s Vulnerable › Vulnerabilities

CVE-2026-55375: canto-saas-api: OAuth credentials exposed in URL query string and exception messages

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-30
• Weakness: CWE-209

Description

canto-saas-api is a PHP library for interacting with the Canto SaaS API. Prior to version 3.0.0, OAuth2Request::getQueryParams() places app_id, app_secret, refresh_token, and code in the URL query string of token POST requests, allowing access logs, proxy logs, and APM traces to persist the credentials in plaintext. When a token request fails, OAuth2::obtainAccessToken() also passes the credential-bearing Guzzle request URI into AuthorizationFailedException, so application logs and error trackers can record the same secrets. An attacker with access to affected telemetry can obtain Canto credentials and use them to request access tokens for the tenant. This issue is fixed in version 3.0.0.

Affected products

• jleehr canto-saas-api: before 3.0.0

References

• https://github.com/jleehr/canto-saas-api/commit/300559fdae5d1bed2dc00a6477f5996833a77339
• https://github.com/jleehr/canto-saas-api/releases/tag/3.0.0
• https://github.com/jleehr/canto-saas-api/security/advisories/GHSA-37pm-83g7-r22v

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