SAP patches a maximum-severity Python SDK flaw that redirects OAuth2 token requests through tenant_subdomain
SAP fixed CVE-2026-89111, a maximum-severity OAuth2 SSRF in its Cloud SDK for Python, in a 20-flaw October 2026 update. A multi-tenant BTP app that lets outside input set tenant_subdomain can send its client credentials to an attacker until it is patched or allowlisted.
The Watch · Security desk
Of 14 SAP security flaws CISA has added to its catalog of actively exploited vulnerabilities since November 2021, three were abused in ransomware attacks.
- Abused in ransomware attacks, claim 8 3 of 14 SAP flaws 21% computed
Abused in ransomware attacks The rest of the 14
| Share | Part | Whole | Percent | Claim |
|---|---|---|---|---|
| Abused in ransomware attacks | 3 SAP flaws | 14 SAP flaws | 21% (computed) | 8 |
What happened
- SAP says remote attackers without privileges can exploit CVE-2026-89111 to steal credentials.
- The Cloud SDK for Python is SAP's official toolkit for building AI agents and Python applications on its Business Technology Platform services.
- Customers who cannot deploy the October patches right away can mitigate temporarily by validating tenant_subdomain values against an allowlist.
- The same batch fixes CVE-2026-89110, a critical broken access control flaw in NetWeaver Visual Composer that remote attackers with limited privileges could use to fully compromise a system.
- It also fixes CVE-2026-89108 in Manufacturing Integration and Intelligence, where an administrator can provision an elevated-privilege account on the underlying Java app.
Why it matters
- Who's exposed exposure SAP scopes the flaw to multi-tenant BTP applications. Teams running those apps need to check how they set tenant_subdomain.
- What it costs cost The allowlist belongs in consumer application code before any SDK call, so each team using the SDK makes and maintains its own change.
- What it sets up precedent Defused flagged the August Commerce Cloud flaw as exploited days after SAP fixed it. We would plan for a window of days on this one.
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The attack requires control of the tenant_subdomain value. SAP's Tuesday advisory reads: "The SAP Cloud SDK for Python contains an OAuth2 SSRF vulnerability affecting multi-tenant BTP applications. An attacker who controls the tenant_subdomain parameter can redirect OAuth2 token requests to an attacker-controlled server, causing client credentials to be exfiltrated." [2]
The advisory tells consumer applications to validate "tenant_subdomain against a known allowlist of registered tenant subdomains before passing it to any SDK call." [7] We think an app that only hands the SDK values from its own tenant registry gives an attacker nothing to redirect. An app that forwards a subdomain taken from a request is the target.
Patching stops new redirects. It does not recover a secret that has already gone to an attacker's server, so we would rotate client credentials on any app that took tenant_subdomain from outside input. The report did not disclose whether anyone has exploited CVE-2026-89111 or which SDK version carries the fix.
SAP flaws have reached attackers before. CISA has added 14 SAP flaws to its exploited-vulnerabilities catalog since November 2021 [8]. Three of them, about 21%, were abused in ransomware attacks [11]. In September, SAP fixed CVE-2026-44756 in the SAP Kernel, which Onapsis named OVERPASS, and Onapsis estimated at the time that over 10,000 internet-facing SAP systems use the vulnerable component [10].
Inside this month's batch, we would queue CVE-2026-89110 beside CVE-2026-89111 and CVE-2026-89108 behind them, going by the access each attacker needs first [4][5].
What to watch
- Whether Defused, Onapsis or anyone else reports exploitation of CVE-2026-89111; the August Commerce Cloud flaw was flagged within days of its fix.
- Whether CISA adds CVE-2026-89111 to its exploited-vulnerabilities catalog, which holds 14 SAP flaws today.
- Whether SAP or a researcher publishes the fixed SDK version and a proof of concept for the tenant_subdomain redirect.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence72
- Adoption
- Not scored
- Hype gap+5
- Incentives
- Not scored
- Confidence78
Perspective Coverage
4 publishers- Builder
- Builder 24%
- Operator
- Operator 64%
- Investor
- Investor 12%
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
CVE-2026-89111, patched in October 2026, can be exploited by remote attackers without privileges to steal credentials.
- [2]
"The SAP Cloud SDK for Python contains an OAuth2 SSRF vulnerability affecting multi-tenant BTP applications. An attacker who controls the tenant_subdomain parameter can redirect OAuth2 token requests to an attacker-controlled server, causing client credentials to be exfiltrated."
- [3]
SAP addressed 20 security flaws across multiple products in its October 2026 security updates, including a maximum-severity vulnerability in the Cloud SDK for Python.
- [4]
CVE-2026-89110 is a critical broken access control vulnerability in SAP NetWeaver Visual Composer that could let remote attackers with limited privileges fully compromise vulnerable systems.
- [5]
CVE-2026-89108, a critical flaw in SAP Manufacturing Integration and Intelligence, lets threat actors with administrator privileges gain admin control over the underlying system by provisioning an elevated-privilege account on the underlying Java app.
- [6]
Customers who cannot immediately deploy the October 2026 SAP patches can temporarily mitigate the issue by using an allowlist to validate tenant_subdomain values.
- [7]
"Consumer applications can mitigate the vulnerability by validating tenant_subdomain against a known allowlist of registered tenant subdomains before passing it to any SDK call."
- [8]
CISA has added 14 SAP security flaws to its catalog of actively exploited vulnerabilities since November 2021, three of which were abused in ransomware attacks.
- [9]
SAP patched CVE-2026-58231 in the Commerce Cloud e-commerce platform in August, and threat intelligence firm Defused flagged it as actively exploited in attacks days after it was addressed.
- [10]
SAP fixed the CVE-2026-44756 memory corruption flaw in the SAP Kernel in September, dubbed OVERPASS by Onapsis researchers who reported it; Onapsis estimated at the time that over 10,000 Internet-facing SAP systems use the vulnerable component and may be exposed.
- [11]
About 21% of the SAP flaws in CISA's exploited-vulnerabilities catalog were abused in ransomware attacks.
- [12]
The SAP Python SDK is the official programmatic toolkit for developing AI agents and Python applications on SAP Business Technology Platform (BTP) services.
Sources
4 independent publishers whose own reporting we read for this story.
- bleepingcomputer.comSAP warns of maximum severity OAuth2 SSRF security flaw
1 article · October 13, 2026
- scworld.comSAP addresses 20 security flaws, including critical Python SDK vulnerability
1 article · October 14, 2026
- securityweek.comSAP Patches Critical NetWeaver, S/4HANA Vulnerabilities
1 article · October 13, 2026
- thecyberexpress.comSAP Patches Critical CVSS 10.0 Flaw in Cloud SDK for Python
1 article · October 14, 2026
Topics and entities
Topics
- Multi-tenant applications
- Enterprise Software Security
- Server-Side Request Forgery
- Patch And Redeploy Latency