SAP Cloud SDK for Python flaw could expose sensitive credentials

What is the SAP Cloud SDK for Python vulnerability?

A critical security flaw has been found in SAP's Cloud SDK for Python, the official client library used by many applications on SAP's Business Technology Platform (BTP). The flaw, tracked as CVE-2026-89111 and given the highest possible CVSS score of 10.0, could allow attackers to steal OAuth2 client credentials. These credentials are used by applications to authenticate with SAP cloud services and often grant broad access to sensitive data or functionality. The Hacker News↗ (opens in a new tab) was the first to report the issue, citing an SAP security advisory.

Who is affected and what versions are vulnerable?

The flaw affects multi-tenant applications on SAP BTP that use the Python SDK and pass a tenant subdomain to the library. An attacker must be able to control this subdomain, which is used to identify which tenant (customer or client) the application is acting on behalf of. The vulnerability was present in all releases of the SDK before version 0.45.2, which was published on 21 August 2026 and introduced a fix. However, The Hacker News found that six later releases (0.53.0 through 0.55.0, published between 10 and 18 September) also missed the fix in certain modules, specifically when using the Destination service. The fix was properly reapplied in version 0.55.1.

Older releases in the 0.36 line (0.36.1 and 0.36.2) also lack the check and are vulnerable. The latest release as of 13 October 2026, version 0.58.4, contains the fix. Users of affected versions are strongly advised to upgrade.

How does the attack work?

The vulnerability is a form of server-side request forgery (SSRF). When an application passes a tenant subdomain to the SDK, the library constructs a URL by inserting the subdomain into a template. If the subdomain contains special characters (like URL delimiters), it can cause the SDK to send the application's OAuth2 client credentials (client ID and secret) to an attacker-controlled server. This could let an attacker capture credentials and use them to impersonate the application or access sensitive data, depending on the permissions granted to the credentials.

The fix added a check that only allows subdomains made up of letters, digits, and hyphens, up to 63 characters. Any value that does not match this pattern is now rejected with an error.

What has SAP said and what should users do?

SAP's advisory recommends upgrading to a fixed version of the SDK. For applications that cannot upgrade immediately, SAP suggests validating tenant subdomains against a list of registered tenants before passing them to the SDK. The advisory does not say whether applications that used a vulnerable version should replace their credentials, nor does it mention any known attacks exploiting the flaw. The fix was first released as a bug fix, and the security advisory followed 53 days later, crediting a GitHub user for reporting the issue.

What is still unclear?

As of now, only The Hacker News has reported on this flaw, and there is no primary source from SAP or a government agency publicly available. It is also unclear whether the six later releases without the check are officially covered by the CVE, as the advisory does not mention them. There are no reports of attacks in the wild, and the potential impact depends on the permissions granted to the stolen credentials.

Practical advice for teams

• Check which version of the SAP Cloud SDK for Python your applications use. Upgrade to at least 0.55.1 or later if possible.
• If you cannot upgrade, ensure tenant subdomains are validated before passing them to the SDK.
• Review your application's use of OAuth2 credentials and consider rotating them if you used a vulnerable version.
• Monitor SAP's official channels for further advisories or clarifications.