Summary
canto-saas-api: OAuth credentials exposed in URL query string and exception messages
Full technical description
In affected versions, the OAuth2 token request sends app_id, app_secret,
refresh_token and code as URL query parameters of the POST request to
https://oauth.<domain>/oauth/api/oauth2/token. Request URLs are commonly
recorded in access logs, proxy logs and APM traces, so the application secret
and refresh token can be persisted in plain text outside the application's
control.
In addition, when the token request fails, the Guzzle exception message ,
which contains the full request URI including the credentials, was passed
unmodified into the AuthorizationFailedException thrown by
OAuth2::obtainAccessToken(). Applications that log exceptions or forward
them to error trackers (e.g. Sentry) may therefore have recorded the app
secret in their logs.
Impact
An attacker with access to web server logs, proxy logs, APM tracing data or
application error logs of a consumer of this library can obtain the Canto
app_secret, refresh_token or authorization code and use them to obtain
access tokens for the Canto tenant.
Patches
Fixed in 3.0.0:
- OAuth credentials are sent in the form-encoded POST body instead of the URL
query string (RFC 6749 §2.3.1).OAuth2Request::getQueryParams()now
returnsnull; the parameters are available viagetFormParams(). - Exception messages are sanitized before being rethrown: the values of
app_secret,refresh_tokenandcodeare masked (including url-encoded,
differently cased and JSON-embedded variants).
Workarounds
If you cannot upgrade:
- Treat web server, proxy and APM logs of systems performing Canto OAuth
requests as secret material and restrict access to them. - Catch
AuthorizationFailedExceptionin your application and strip the query
string from the message before logging or forwarding it.
If your logs may have been exposed, rotate the affected Canto app secret.
Impact
CVE-2026-55375 has a CVSS score of 5.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.0.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-55375? CVE-2026-55375 is a medium-severity security vulnerability in jleehr/canto-saas-api (composer), affecting versions <= 2.0.0. It is fixed in 3.0.0.
- How severe is CVE-2026-55375? CVE-2026-55375 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of jleehr/canto-saas-api are affected by CVE-2026-55375? jleehr/canto-saas-api (composer) versions <= 2.0.0 is affected.
- Is there a fix for CVE-2026-55375? Yes. CVE-2026-55375 is fixed in 3.0.0. Upgrade to this version or later.
- Is CVE-2026-55375 exploitable, and should I be worried? Whether CVE-2026-55375 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55375 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55375? Upgrade
jleehr/canto-saas-apito 3.0.0 or later.