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fix(saml): clarify signature validation behavior (CVE-2026-14917) #6494

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lena-larionova merged 2 commits into from
Aug 7, 2026
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fix(saml): clarify signature validation behavior (CVE-2026-14917) #6494

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fix(saml): clarify signature validation behavior (CVE-2026-14917)
findns94 Jul 29, 2026
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lena-larionova Jul 31, 2026
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10 changes: 6 additions & 4 deletions app/_how-tos/gateway/enable-saml-authentication-with-microsoft-entra.md
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Expand Up @@ -107,10 +107,12 @@ Enable the [SAML plugin](/plugins/saml/) and provide the information to connect
We also need to provide a value for [`config.session_secret`](/plugins/saml/reference/#schema--config-session-secret), which should be a random 32-character string.

{:.danger}
> This example keeps [`validate_assertion_signature`](/plugins/saml/reference/#schema--config-validate-assertion-signature) set to its default value of `true`, which requires a valid `idp_certificate`.
> If you only want to test the authentication flow without configuring a signing certificate, you can manually set `validate_assertion_signature` to `false`.
> Disabling signature validation is **not secure**. **Do not disable signature validation in production.**

> This example keeps [`validate_assertion_signature`](/plugins/saml/reference/#schema--config-validate-assertion-signature) at its default value of `true`, which requires a valid `idp_certificate`.
> The plugin validates the SAML response signature whenever you configure an `idp_certificate`, even if you set `validate_assertion_signature` to `false`.
> <br><br>
> The plugin skips signature validation only when `validate_assertion_signature` is `false` and no `idp_certificate` is set. It then accepts unsigned responses and logs a warning.
> This state is **not secure**, as an attacker can impersonate any user.
> Always set `idp_certificate`. Never disable signature validation in production.
{% entity_examples %}
entities:
plugins:
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4 changes: 4 additions & 0 deletions app/_kong_plugins/saml/index.md
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Expand Up @@ -75,6 +75,10 @@ The minimum configuration required is:
information from the IdP.
- The issuer (`issuer`): This is the unique identifier of the IdP application.

{:.warning}
> The plugin validates the SAML response signature whenever you set `idp_certificate`, even when [`validate_assertion_signature`](/plugins/saml/reference/#schema--config-validate-assertion-signature) is `false`.
> If you set `validate_assertion_signature` to `false` and don't configure `idp_certificate`, the plugin skips signature validation and accepts unsigned responses, which is insecure. Always set `idp_certificate`.

The plugin currently supports SAML 2.0 with Microsoft Entra. Refer to the
[Microsoft Entra SAML documentation](https://learn.microsoft.com/en-us/entra/architecture/auth-saml)
for more information about SAML authentication with Azure AD.
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