TI-2026-39954 Aliases CVE-2026-55375 GHSA-37pm-83g7-r22v

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

LOW 24CWE-209Published 2026-09-15 · Updated 2026-09-15

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: High
Impact type: Information disclosure
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-209.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00383 32nd percentileScored 2026-11-07

Fix Fixed canto-saas-api (jleehr): 3.0.0jleehr/canto-saas-api (Packagist): 3.0.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
jleehr	canto-saas-api	before 3.0.0	3.0.0	Patch available	CNA
—	jleehr/canto-saas-api (Packagist)	before 3.0.0	3.0.0	Patch available	GHSA-37pm-83g7-r22v

canto-saas-api Vendorjleehr Affected before 3.0.0 Fixed in 3.0.0 Patch available CNA
jleehr/canto-saas-api (Packagist) Vendor— Affected before 3.0.0 Fixed in 3.0.0 Patch available GHSA-37pm-83g7-r22v

Remediation

Fix · CNA canto-saas-api (jleehr) Fixed in 3.0.0
Fix · GHSA-37pm-83g7-r22v jleehr/canto-saas-api (Packagist) Fixed in 3.0.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-55375
2026-10-03 Alias added: GHSA-37pm-83g7-r22v

References

Other 4

TI-2026-39953 canto-saas-api: Authenticated API requests can be redirected via unencoded path variables CVSS 3.1MEDIUM 4.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences